diff --git a/spine-ts/spine-webgl/src/SpineWebComponentWidget.ts b/spine-ts/spine-webgl/src/SpineWebComponentWidget.ts
index 7df081510..842ce0266 100644
--- a/spine-ts/spine-webgl/src/SpineWebComponentWidget.ts
+++ b/spine-ts/spine-webgl/src/SpineWebComponentWidget.ts
@@ -858,8 +858,8 @@ export class SpineWebComponentWidget extends HTMLElement implements Disposable,
 
 	disconnectedCallback (): void {
 		window.removeEventListener("DOMContentLoaded", this.DOMContentLoadedHandler);
-		const index = this.overlay!.skeletonList.indexOf(this);
-		if (index !== -1) {
+		const index = this.overlay?.skeletonList.indexOf(this);
+		if (index > 0) {
 			this.overlay!.skeletonList.splice(index, 1);
 		}
 	}