diff --git a/blocks/library/heading/index.js b/blocks/library/heading/index.js
index 6b08226990a4a..40870e58d437f 100644
--- a/blocks/library/heading/index.js
+++ b/blocks/library/heading/index.js
@@ -1,7 +1,7 @@
 /**
  * External dependencies
  */
-import { isString, isObject } from 'lodash';
+import { isObject } from 'lodash';
 
 /**
  * WordPress dependencies
@@ -44,9 +44,9 @@ registerBlockType( 'core/heading', {
 				transform: ( { content, ...attrs } ) => {
 					const isMultiParagraph = Array.isArray( content ) && isObject( content[ 0 ] ) && content[ 0 ].type === 'p';
 					if ( isMultiParagraph ) {
-						const headingContent = isString( content[ 0 ] )
-							? content[ 0 ]
-							: content[ 0 ].props.children;
+						const headingContent = isObject( content[ 0 ] ) && content[ 0 ].type === 'p'
+							? content[ 0 ].props.children
+							: content[ 0 ];
 						const heading = createBlock( 'core/heading', {
 							content: headingContent,
 						} );
diff --git a/blocks/library/quote/index.js b/blocks/library/quote/index.js
index 7c84044af0e0d..9cf3496a8a68b 100644
--- a/blocks/library/quote/index.js
+++ b/blocks/library/quote/index.js
@@ -90,7 +90,9 @@ registerBlockType( 'core/quote', {
 				transform: ( { value, citation, ...attrs } ) => {
 					const isMultiParagraph = Array.isArray( value ) && isObject( value[ 0 ] ) && value[ 0 ].type === 'p';
 					const headingElement = isMultiParagraph ? value[ 0 ] : value;
-					const headingContent = isString( headingElement ) ? headingElement : headingElement.props.children;
+					const headingContent = isObject( headingElement ) && value[ 0 ].type === 'p'
+						? headingElement.props.children
+						: headingElement;
 					if ( isMultiParagraph || citation ) {
 						const heading = createBlock( 'core/heading', {
 							content: headingContent,