fix

packages/svelte/src/internal/client/dom/blocks/boundary.js

@@ -111,6 +111,10 @@ export function boundary(node, props, boundary_fn) {
 
 				if (suspend_count++ === 0) {
 					queue_micro_task(() => {
+						if (suspended_effect) {
+							return;
+						}
+
 						var effect = boundary_effect;
 						suspended_effect = boundary_effect;
 
@@ -149,7 +153,12 @@ export function boundary(node, props, boundary_fn) {
 					return false;
 				}
 
-				if (--suspend_count === 0 && suspended_effect !== null) {
+				if (--suspend_count === 0) {
+					queue_micro_task(() => {
+						if (!suspended_effect) {
+							return;
+						}
+
 						if (boundary_effect) {
 							destroy_effect(boundary_effect);
 						}
@@ -157,6 +166,7 @@ export function boundary(node, props, boundary_fn) {
 						suspended_effect = null;
 						anchor.before(/** @type {DocumentFragment} */ (suspended_fragment));
 						resume_effect(boundary_effect);
+					});
 				}
 
 				return true;