diff --git a/src/fix_property_atom.cpp b/src/fix_property_atom.cpp
index 24704a12ad..95e25c59b2 100644
--- a/src/fix_property_atom.cpp
+++ b/src/fix_property_atom.cpp
@@ -325,12 +325,12 @@ void FixPropertyAtom::read_data_section(char *keyword, int n, char *buf, tagint
 }
 
 /* ----------------------------------------------------------------------
-   return # of lines in section of data file labeled by keyword
+   return # of lines in section of data file labeled by keyword. -1 signals use # of added atoms
 ------------------------------------------------------------------------- */
 
 bigint FixPropertyAtom::read_data_skip_lines(char * /*keyword*/)
 {
-  return atom->natoms;
+  return -1;
 }
 
 /* ----------------------------------------------------------------------
diff --git a/src/read_data.cpp b/src/read_data.cpp
index ee6399a2d3..5317a4217a 100644
--- a/src/read_data.cpp
+++ b/src/read_data.cpp
@@ -875,10 +875,13 @@ void ReadData::command(int narg, char **arg)
         int i;
         for (i = 0; i < nfix; i++)
           if (strcmp(keyword, fix_section[i]) == 0) {
-            if (firstpass)
+            if (firstpass) {
               fix(fix_index[i], keyword);
-            else
-              skip_lines(fix_index[i]->read_data_skip_lines(keyword));
+            } else {
+              auto nskip = fix_index[i]->read_data_skip_lines(keyword);
+              if (nskip < 0) nskip = natoms;
+              skip_lines(nskip);
+            }
             break;
           }
         if (i == nfix)
@@ -2225,6 +2228,7 @@ void ReadData::fix(Fix *ifix, char *keyword)
   int nchunk, eof;
 
   bigint nline = ifix->read_data_skip_lines(keyword);
+  if (nline < 0) nline = natoms;
 
   bigint nread = 0;
   while (nread < nline) {