diff --git a/UnitTestContrib/test/unit/AddressTests.pm b/UnitTestContrib/test/unit/AddressTests.pm
index 8f6caca87a..1721a37e65 100644
--- a/UnitTestContrib/test/unit/AddressTests.pm
+++ b/UnitTestContrib/test/unit/AddressTests.pm
@@ -32,7 +32,6 @@ my %test_roundtrip_range = (
     ],
     tompaths => [
         undef,
-        ['attachment'],
         [ 'attachment', 'Attachment' ],
         [ 'attachment', 'Attach.ent' ],
         [ 'attachment', 'Atta.h.ent' ],
diff --git a/core/lib/Foswiki/Address.pm b/core/lib/Foswiki/Address.pm
index 68e2f70ec7..ca6d253134 100644
--- a/core/lib/Foswiki/Address.pm
+++ b/core/lib/Foswiki/Address.pm
@@ -1448,8 +1448,8 @@ sub isValid {
                           and scalar( @{ $this->{tompath} } ) )
                       if DEBUG;
                     ASSERT(
-                        not(    $this->{topmath}->[0]
-                            and $this->{topmath}->[0] eq 'attachment' )
+                        not(    $this->{tompath}->[0]
+                            and $this->{tompath}->[0] eq 'attachment' )
                     ) if DEBUG;
                     ASSERT( $pathtypes{ $this->{tompath}->[0] } ) if DEBUG;
                     $this->{type} =