diff --git a/src/wp-includes/block-supports/elements.php b/src/wp-includes/block-supports/elements.php
index 740d522b0cf40..34960956519a4 100644
--- a/src/wp-includes/block-supports/elements.php
+++ b/src/wp-includes/block-supports/elements.php
@@ -17,7 +17,10 @@
  * @return string                Filtered block content.
  */
 function wp_render_elements_support( $block_content, $block ) {
-	$link_color = _wp_array_get( $block['attrs'], array( 'style', 'elements', 'link', 'color', 'text' ), null );
+	$link_color = null;
+	if ( ! empty( $block['attrs'] ) ) {
+		$link_color = _wp_array_get( $block['attrs'], array( 'style', 'elements', 'link', 'color', 'text' ), null );
+	}
 
 	/*
 	* For now we only care about link color.
diff --git a/src/wp-includes/class-wp-theme-json.php b/src/wp-includes/class-wp-theme-json.php
index 5aef6f1886cb6..5580e39285df7 100644
--- a/src/wp-includes/class-wp-theme-json.php
+++ b/src/wp-includes/class-wp-theme-json.php
@@ -609,6 +609,28 @@ function ( $carry, $element ) {
 		return $selector . '{' . $declaration_block . '}';
 	}
 
+	/**
+	 * Function that appends a sub-selector to a existing one.
+	 *
+	 * Given the compounded $selector "h1, h2, h3"
+	 * and the $to_append selector ".some-class" the result will be
+	 * "h1.some-class, h2.some-class, h3.some-class".
+	 *
+	 * @param string $selector Original selector.
+	 * @param string $to_append Selector to append.
+	 *
+	 * @return string
+	 */
+	private static function append_to_selector( $selector, $to_append ) {
+		$new_selectors = array();
+		$selectors     = explode( ',', $selector );
+		foreach ( $selectors as $sel ) {
+			$new_selectors[] = $sel . $to_append;
+		}
+
+		return implode( ',', $new_selectors );
+	}
+
 	/**
 	 * Given a settings array, it returns the generated rulesets
 	 * for the preset classes.
@@ -633,7 +655,7 @@ private static function compute_preset_classes( $settings, $selector ) {
 			foreach ( $values as $value ) {
 				foreach ( $preset['classes'] as $class ) {
 					$stylesheet .= self::to_ruleset(
-						$selector . '.has-' . $value['slug'] . '-' . $class['class_suffix'],
+						self::append_to_selector( $selector, '.has-' . $value['slug'] . '-' . $class['class_suffix'] ),
 						array(
 							array(
 								'name'  => $class['property_name'],
diff --git a/tests/phpunit/tests/theme/wpThemeJson.php b/tests/phpunit/tests/theme/wpThemeJson.php
index 12c89fad5ba7b..aceb3bd73bc5f 100644
--- a/tests/phpunit/tests/theme/wpThemeJson.php
+++ b/tests/phpunit/tests/theme/wpThemeJson.php
@@ -619,6 +619,28 @@ function test_get_editor_settings_no_theme_support() {
 		$this->assertEqualSetsWithIndex( $expected, $actual );
 	}
 
+	/**
+	 * Function that appends a sub-selector to a existing one.
+	 *
+	 * Given the compounded $selector "h1, h2, h3"
+	 * and the $to_append selector ".some-class" the result will be
+	 * "h1.some-class, h2.some-class, h3.some-class".
+	 *
+	 * @param string $selector Original selector.
+	 * @param string $to_append Selector to append.
+	 *
+	 * @return string
+	 */
+	private static function append_to_selector( $selector, $to_append ) {
+		$new_selectors = array();
+		$selectors     = explode( ',', $selector );
+		foreach ( $selectors as $sel ) {
+			$new_selectors[] = $sel . $to_append;
+		}
+
+		return implode( ',', $new_selectors );
+	}
+
 	/**
 	 * @ticket 52991
 	 */