diff --git a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.C b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.C
index 11e837c530..d60692571d 100644
--- a/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.C
+++ b/src/OpenFOAM/matrices/lduMatrix/lduAddressing/lduInterface/lduCalculatedProcessorField/lduCalculatedProcessorField.C
@@ -60,13 +60,7 @@ Foam::lduCalculatedProcessorField<Type>::lduCalculatedProcessorField
 template<class Type>
 bool Foam::lduCalculatedProcessorField<Type>::ready() const
 {
-    if (!UPstream::finishedRequest(this->sendRequest_)) return false;
-    this->sendRequest_ = -1;
-
-    if (!UPstream::finishedRequest(this->recvRequest_)) return false;
-    this->recvRequest_ = -1;
-
-    return true;
+    return UPstream::finishedRequestPair(recvRequest_, sendRequest_);
 }
 
 
@@ -173,10 +167,12 @@ void Foam::lduCalculatedProcessorField<Type>::updateInterfaceMatrix
         return;
     }
 
-    // Treat send as finished when recv is done
-    UPstream::waitRequest(recvRequest_);
-    recvRequest_ = -1;
-    sendRequest_ = -1;
+    // Require receive data. Update the send request state.
+    // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+    UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+    if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
+
 
     // Consume straight from receive buffer. Note use of our own
     // helper to avoid using fvPatch addressing
diff --git a/src/OpenFOAM/matrices/lduMatrix/solvers/GAMG/interfaceFields/processorGAMGInterfaceField/processorGAMGInterfaceField.C b/src/OpenFOAM/matrices/lduMatrix/solvers/GAMG/interfaceFields/processorGAMGInterfaceField/processorGAMGInterfaceField.C
index 8309c1b31a..0e4b221535 100644
--- a/src/OpenFOAM/matrices/lduMatrix/solvers/GAMG/interfaceFields/processorGAMGInterfaceField/processorGAMGInterfaceField.C
+++ b/src/OpenFOAM/matrices/lduMatrix/solvers/GAMG/interfaceFields/processorGAMGInterfaceField/processorGAMGInterfaceField.C
@@ -171,10 +171,11 @@ void Foam::processorGAMGInterfaceField::updateInterfaceMatrix
     {
         // Fast path: consume straight from receive buffer
 
-        // Treat send as finished when recv is done
-        UPstream::waitRequest(recvRequest_);
-        recvRequest_ = -1;
-        sendRequest_ = -1;
+        // Require receive data. Update the send request state.
+        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
     else
     {
diff --git a/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.C b/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.C
index d65ea2637d..70935bcf79 100644
--- a/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.C
+++ b/src/finiteArea/fields/faPatchFields/constraint/processor/processorFaPatchField.C
@@ -176,13 +176,7 @@ Foam::processorFaPatchField<Type>::processorFaPatchField
 template<class Type>
 bool Foam::processorFaPatchField<Type>::ready() const
 {
-    if (!UPstream::finishedRequest(sendRequest_)) return false;
-    sendRequest_ = -1;
-
-    if (!UPstream::finishedRequest(recvRequest_)) return false;
-    recvRequest_ = -1;
-
-    return true;
+    return UPstream::finishedRequestPair(recvRequest_, sendRequest_);
 }
 
 
@@ -207,7 +201,7 @@ void Foam::processorFaPatchField<Type>::initEvaluate
     const Pstream::commsTypes commsType
 )
 {
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         this->patchInternalField(sendBuf_);
 
@@ -259,16 +253,17 @@ void Foam::processorFaPatchField<Type>::evaluate
     const Pstream::commsTypes commsType
 )
 {
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         if (commsType == UPstream::commsTypes::nonBlocking)
         {
             // Fast path. Received into *this
 
-            // Treat send as finished when recv is done
-            UPstream::waitRequest(recvRequest_);
-            recvRequest_ = -1;
-            sendRequest_ = -1;
+            // Require receive data. Update the send request state.
+            // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+            UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+            if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
         }
         else
         {
@@ -373,10 +368,11 @@ void Foam::processorFaPatchField<Type>::updateInterfaceMatrix
     {
         // Fast path: consume straight from receive buffer
 
-        // Treat send as finished when recv is done
-        UPstream::waitRequest(recvRequest_);
-        recvRequest_ = -1;
-        sendRequest_ = -1;
+        // Require receive data. Update the send request state.
+        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
     else
     {
@@ -479,10 +475,11 @@ void Foam::processorFaPatchField<Type>::updateInterfaceMatrix
     {
         // Fast path: consume straight from receive buffer
 
-        // Treat send as finished when recv is done
-        UPstream::waitRequest(recvRequest_);
-        recvRequest_ = -1;
-        sendRequest_ = -1;
+        // Require receive data. Update the send request state.
+        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
     else
     {
diff --git a/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.C b/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.C
index 875c98105f..25e6ee5a23 100644
--- a/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.C
+++ b/src/finiteVolume/fields/fvPatchFields/constraint/calculatedProcessor/calculatedProcessorFvPatchField.C
@@ -76,13 +76,7 @@ Foam::calculatedProcessorFvPatchField<Type>::calculatedProcessorFvPatchField
 template<class Type>
 bool Foam::calculatedProcessorFvPatchField<Type>::ready() const
 {
-    if (!UPstream::finishedRequest(this->sendRequest_)) return false;
-    this->sendRequest_ = -1;
-
-    if (!UPstream::finishedRequest(this->recvRequest_)) return false;
-    this->recvRequest_ = -1;
-
-    return true;
+    return UPstream::finishedRequestPair(recvRequest_, sendRequest_);
 }
 
 
@@ -109,7 +103,7 @@ void Foam::calculatedProcessorFvPatchField<Type>::initEvaluate
     const Pstream::commsTypes commsType
 )
 {
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         if (!is_contiguous<Type>::value)
         {
@@ -164,12 +158,13 @@ void Foam::calculatedProcessorFvPatchField<Type>::evaluate
     const Pstream::commsTypes commsType
 )
 {
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
-        // Treat send as finished when recv is done
-        UPstream::waitRequest(recvRequest_);
-        recvRequest_ = -1;
-        sendRequest_ = -1;
+        // Require receive data. Update the send request state.
+        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
 }
 
@@ -278,14 +273,16 @@ void Foam::calculatedProcessorFvPatchField<Type>::updateInterfaceMatrix
         return;
     }
 
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
-        // Treat send as finished when recv is done
-        UPstream::waitRequest(recvRequest_);
-        recvRequest_ = -1;
-        sendRequest_ = -1;
+        // Require receive data. Update the send request state.
+        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
 
+
     // Consume straight from receive buffer. Note use of our own
     // helper to avoid using fvPatch addressing
     addToInternalField(result, !add, coeffs, scalarRecvBuf_);
diff --git a/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.C b/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.C
index b5350e4f3f..3fdec71d96 100644
--- a/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.C
+++ b/src/finiteVolume/fields/fvPatchFields/constraint/processor/processorFvPatchField.C
@@ -111,6 +111,7 @@ Foam::processorFvPatchField<Type>::processorFvPatchField
     if (!isA<processorFvPatch>(this->patch()))
     {
         FatalErrorInFunction
+            << "\n    patch type '" << p.type()
             << "' not constraint type '" << typeName << "'"
             << "\n    for patch " << p.name()
             << " of field " << this->internalField().name()
@@ -177,13 +178,7 @@ Foam::processorFvPatchField<Type>::processorFvPatchField
 template<class Type>
 bool Foam::processorFvPatchField<Type>::ready() const
 {
-    if (!UPstream::finishedRequest(sendRequest_)) return false;
-    sendRequest_ = -1;
-
-    if (!UPstream::finishedRequest(recvRequest_)) return false;
-    recvRequest_ = -1;
-
-    return true;
+    return UPstream::finishedRequestPair(recvRequest_, sendRequest_);
 }
 
 
@@ -208,7 +203,7 @@ void Foam::processorFvPatchField<Type>::initEvaluate
     const Pstream::commsTypes commsType
 )
 {
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         this->patchInternalField(sendBuf_);
 
@@ -264,7 +259,7 @@ void Foam::processorFvPatchField<Type>::evaluate
     const Pstream::commsTypes commsType
 )
 {
-    if (Pstream::parRun())
+    if (UPstream::parRun())
     {
         if
         (
@@ -274,10 +269,11 @@ void Foam::processorFvPatchField<Type>::evaluate
         {
             // Fast path: received into *this
 
-            // Treat send as finished when recv is done
-            UPstream::waitRequest(recvRequest_);
-            recvRequest_ = -1;
-            sendRequest_ = -1;
+            // Require receive data. Update the send request state.
+            // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+            UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+            if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
         }
         else
         {
@@ -402,10 +398,11 @@ void Foam::processorFvPatchField<Type>::updateInterfaceMatrix
     {
         // Fast path: consume straight from receive buffer
 
-        // Treat send as finished when recv is done
-        UPstream::waitRequest(recvRequest_);
-        recvRequest_ = -1;
-        sendRequest_ = -1;
+        // Require receive data. Update the send request state.
+        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
     else
     {
@@ -523,10 +520,11 @@ void Foam::processorFvPatchField<Type>::updateInterfaceMatrix
     {
         // Fast path: consume straight from receive buffer
 
-        // Treat send as finished when recv is done
-        UPstream::waitRequest(recvRequest_);
-        recvRequest_ = -1;
-        sendRequest_ = -1;
+        // Require receive data. Update the send request state.
+        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
     else
     {
diff --git a/src/overset/lduPrimitiveProcessorInterface/GAMG/calculatedProcessorGAMGInterfaceField.C b/src/overset/lduPrimitiveProcessorInterface/GAMG/calculatedProcessorGAMGInterfaceField.C
index cc58546967..adf9b74a17 100644
--- a/src/overset/lduPrimitiveProcessorInterface/GAMG/calculatedProcessorGAMGInterfaceField.C
+++ b/src/overset/lduPrimitiveProcessorInterface/GAMG/calculatedProcessorGAMGInterfaceField.C
@@ -172,10 +172,11 @@ void Foam::calculatedProcessorGAMGInterfaceField::updateInterfaceMatrix
     {
         // Fast path: consume straight from receive buffer
 
-        // Treat send as finished when recv is done
-        UPstream::waitRequest(recvRequest_);
-        recvRequest_ = -1;
-        sendRequest_ = -1;
+        // Require receive data. Update the send request state.
+        // OR: UPstream::waitRequestPair(recvRequest_, sendRequest_);
+
+        UPstream::waitRequest(recvRequest_); recvRequest_ = -1;
+        if (UPstream::finishedRequest(sendRequest_)) sendRequest_ = -1;
     }
     else
     {