diff --git a/packages/block-editor/src/components/rich-text/index.js b/packages/block-editor/src/components/rich-text/index.js
index 53b3d85e5dbd6e..ee364e8c3beaeb 100644
--- a/packages/block-editor/src/components/rich-text/index.js
+++ b/packages/block-editor/src/components/rich-text/index.js
@@ -159,6 +159,8 @@ function RichTextWrapper(
 	// retreived from the store on merge.
 	// To do: fix this somehow.
 	const { selectionStart, selectionEnd, isSelected } = useSelect( selector );
+	const { getSelectionStart, getSelectionEnd, getBlockRootClientId } =
+		useSelect( blockEditorStore );
 	const { selectionChange } = useDispatch( blockEditorStore );
 	const multilineTag = getMultilineTag( multiline );
 	const adjustedAllowedFormats = getAllowedFormats( {
@@ -195,6 +197,18 @@ function RichTextWrapper(
 			const unset = start === undefined && end === undefined;
 
 			if ( typeof start === 'number' || unset ) {
+				// If we are only setting the start (or the end below), which
+				// means a partial selection, and we're not updating a selection
+				// with the same client ID, abort. This means the selected block
+				// is a parent block.
+				if (
+					end === undefined &&
+					getBlockRootClientId( clientId ) !==
+						getBlockRootClientId( getSelectionEnd().clientId )
+				) {
+					return;
+				}
+
 				selection.start = {
 					clientId,
 					attributeKey: identifier,
@@ -203,6 +217,14 @@ function RichTextWrapper(
 			}
 
 			if ( typeof end === 'number' || unset ) {
+				if (
+					start === undefined &&
+					getBlockRootClientId( clientId ) !==
+						getBlockRootClientId( getSelectionStart().clientId )
+				) {
+					return;
+				}
+
 				selection.end = {
 					clientId,
 					attributeKey: identifier,