diff --git a/fhem/FHEM/33_readingsGroup.pm b/fhem/FHEM/33_readingsGroup.pm
index 5ee3816ff..11cdd5412 100644
--- a/fhem/FHEM/33_readingsGroup.pm
+++ b/fhem/FHEM/33_readingsGroup.pm
@@ -362,7 +362,7 @@ readingsGroup_2html($)
     #foreach my $regex (@list) {
     for( my $i = 0; $i <= $#list; ++$i ) {
       my $regex = $list[$i];
-      while ($regex && $regex =~ m/^</ && $regex !~ m/>$/ && $list[++$i] ) {
+      while ($regex && $regex =~ m/^</ && $regex !~ m/>$/ && defined($list[++$i]) ) {
         $regex .= ",". $list[$i];
       }
       my $h = $h;
@@ -659,7 +659,7 @@ readingsGroup_Notify($$)
         #foreach my $regex (@list) {
         for( my $i = 0; $i <= $#list; ++$i ) {
         my $regex = $list[$i];
-          while ($regex && $regex =~ m/^</ && $regex !~ m/>$/ && $list[++$i] ) {
+          while ($regex && $regex =~ m/^</ && $regex !~ m/>$/ && defined($list[++$i]) ) {
             $regex .= ",". $list[$i];
           }
           next if( $reading eq "state" && !$show_state && (!defined($regex) || $regex ne "state") );