diff --git a/packages/runtime-vapor/src/block.ts b/packages/runtime-vapor/src/block.ts
index 50a453dc4..b6101efe8 100644
--- a/packages/runtime-vapor/src/block.ts
+++ b/packages/runtime-vapor/src/block.ts
@@ -70,7 +70,8 @@ export class DynamicFragment extends VaporFragment {
       // if current nodes is a DynamicFragment, call its update with the fallback
       // to handle nested dynamic fragment
       if (this.nodes instanceof DynamicFragment) {
-        this.nodes.update(this.fallback)
+        if (!this.nodes.fallback) this.nodes.fallback = this.fallback
+        this.nodes.update(this.nodes.fallback)
       } else {
         this.nodes =
           (this.scope || (this.scope = new EffectScope())).run(this.fallback) ||