diff --git a/packages/runtime-dom/src/apiCustomElement.ts b/packages/runtime-dom/src/apiCustomElement.ts
index aeeaeec9b9f..349ff5ef150 100644
--- a/packages/runtime-dom/src/apiCustomElement.ts
+++ b/packages/runtime-dom/src/apiCustomElement.ts
@@ -280,7 +280,7 @@ export class VueElement
     // avoid resolving component if it's not connected
     if (!this.isConnected) return
 
-    if (!this.shadowRoot) {
+    if (!this.shadowRoot && !this._instance) {
       this._parseSlots()
     }
     this._connected = true