Index: /branches/release-39/lib/MT/CMS/Entry.pm
===================================================================
--- /branches/release-39/lib/MT/CMS/Entry.pm (revision 2514)
+++ /branches/release-39/lib/MT/CMS/Entry.pm (revision 2536)
@@ -1355,4 +1355,5 @@
         $placements_updated = 1;
     }
+    my @add_cat_obj;
     for my $cat_id (@add_cat) {
         my $cat = $cat_class->load($cat_id);
@@ -1371,8 +1372,11 @@
           );
         $placements_updated = 1;
+        push @add_cat_obj, $cat;
     }
     if ($placements_updated) {
+        unshift @add_cat_obj, $obj->cache_property('category')
+          if $obj->cache_property('category');
         $obj->cache_property( 'categories', undef, [] );
-        $obj->cache_property( 'categories', undef, \@add_cat );
+        $obj->cache_property( 'categories', undef, \@add_cat_obj );
     }