diff --git a/.changeset/silver-penguins-juggle.md b/.changeset/silver-penguins-juggle.md
new file mode 100644
index 000000000..700867271
--- /dev/null
+++ b/.changeset/silver-penguins-juggle.md
@@ -0,0 +1,5 @@
+---
+'@lion/overlays': patch
+---
+
+Add a guard for content wrapper containing the content node before appending to the renderTarget. This prevents unhandled rejection.
diff --git a/packages/overlays/src/OverlayController.js b/packages/overlays/src/OverlayController.js
index 81ffd4caa..18a6a8650 100644
--- a/packages/overlays/src/OverlayController.js
+++ b/packages/overlays/src/OverlayController.js
@@ -298,7 +298,8 @@ export class OverlayController {
       this._renderTarget.appendChild(this.contentNode);
     } else {
       const isInsideRenderTarget = this._renderTarget === this._contentWrapperNode.parentNode;
-      if (!isInsideRenderTarget) {
+      const nodeContainsTarget = this._contentWrapperNode.contains(this._renderTarget);
+      if (!isInsideRenderTarget && !nodeContainsTarget) {
         // contentWrapperNode becomes the direct (non projected) parent of contentNode
         this._renderTarget.appendChild(this._contentWrapperNode);
       }