diff --git a/packages/runtime-core/src/componentSlots.ts b/packages/runtime-core/src/componentSlots.ts
index 6114f6c86cf..285f1e17ce9 100644
--- a/packages/runtime-core/src/componentSlots.ts
+++ b/packages/runtime-core/src/componentSlots.ts
@@ -180,7 +180,7 @@ const assignSlots = (
     // when rendering the optimized slots by manually written render function,
     // do not copy the `slots._` compiler flag so that `renderSlot` creates
     // slot Fragment with BAIL patchFlag to force full updates
-    if (optimized || !isInternalKey(key)) {
+    if (optimized || (key !== '_' && key !== '__')) {
       slots[key] = children[key]
     }
   }