diff --git a/Runtime/LibEcs/GroupCore.cs b/Runtime/LibEcs/GroupCore.cs
index eb734bf3..29db1858 100644
--- a/Runtime/LibEcs/GroupCore.cs
+++ b/Runtime/LibEcs/GroupCore.cs
@@ -250,6 +250,8 @@ internal void RemoveFast(int entityID)
 
       if (i < --length)
         Array.Copy(entities, i + 1, entities, i, length - i);
+      
+      flagChanged = true;
     }
 
     //===============================//