diff --git a/src/engine/modules/property-set.c b/src/engine/modules/property-set.c
index 21e35d5ab..aee1f2ff0 100644
--- a/src/engine/modules/property-set.c
+++ b/src/engine/modules/property-set.c
@@ -82,6 +82,7 @@ static void ps_map_destroy( struct ps_map * map )
         for ( pos = map->table[ i ]; pos; )
         {
             struct ps_map_entry * tmp = pos->next;
+            object_free( pos->value );
             BJAM_FREE( pos );
             pos = tmp;
         }
@@ -164,7 +165,7 @@ LIST * property_set_create( FRAME * frame, int flags )
             list_new( object_new( "property-set" ) ), 0 );
         LISTITER iter, end;
         object_free( rulename );
-        pos->value = list_front( val );
+        pos->value = object_copy( list_front( val ) );
         var_set( bindmodule( pos->value ), varname, unique, VAR_SET );
         object_free( varname );