diff --git a/packages/block-editor/src/components/use-block-drop-zone/index.js b/packages/block-editor/src/components/use-block-drop-zone/index.js
index 529eb199fb76a0..d4acb0aaee2432 100644
--- a/packages/block-editor/src/components/use-block-drop-zone/index.js
+++ b/packages/block-editor/src/components/use-block-drop-zone/index.js
@@ -148,6 +148,10 @@ export function getDropTargetPosition(
 		} ) => {
 			const rect = getBoundingClientRect();
 
+			if ( ! rect ) {
+				return;
+			}
+
 			let [ distance, edge ] = getDistanceToNearestEdge(
 				position,
 				rect,
@@ -428,10 +432,14 @@ export default function useBlockDropZone( {
 					return {
 						isUnmodifiedDefaultBlock:
 							getIsUnmodifiedDefaultBlock( block ),
-						getBoundingClientRect: () =>
-							ownerDocument
-								.getElementById( `block-${ clientId }` )
-								.getBoundingClientRect(),
+						getBoundingClientRect: () => {
+							const blockElement = ownerDocument.getElementById(
+								`block-${ clientId }`
+							);
+							return blockElement
+								? blockElement.getBoundingClientRect()
+								: null;
+						},
 						blockIndex: getBlockIndex( clientId ),
 						blockOrientation:
 							getBlockListSettings( clientId )?.orientation,
diff --git a/packages/block-library/src/post-comments-link/edit.js b/packages/block-library/src/post-comments-link/edit.js
index e90734e9740bb3..24a5b9a81e8920 100644
--- a/packages/block-library/src/post-comments-link/edit.js
+++ b/packages/block-library/src/post-comments-link/edit.js
@@ -60,7 +60,13 @@ function PostCommentsLinkEdit( { context, attributes, setAttributes } ) {
 	);
 
 	if ( ! post ) {
-		return null;
+		return (
+			<div { ...blockProps }>
+				<Warning>
+					{ __( 'Post Comments Link block: post not found.' ) }
+				</Warning>
+			</div>
+		);
 	}
 
 	const { link } = post;