diff --git a/lib/block-supports/border.php b/lib/block-supports/border.php
index 1a54371d082e1..bd4c772675a5e 100644
--- a/lib/block-supports/border.php
+++ b/lib/block-supports/border.php
@@ -142,7 +142,7 @@ function gutenberg_apply_border_support( $block_type, $block_attributes ) {
  */
 function gutenberg_has_border_feature_support( $block_type, $feature, $default_value = false ) {
 	// Check if all border support features have been opted into via `"__experimentalBorder": true`.
-	if ( property_exists( $block_type, 'supports' ) ) {
+	if ( $block_type instanceof WP_Block_Type ) {
 		$block_type_supports_border = $block_type->supports['__experimentalBorder'] ?? $default_value;
 		if ( true === $block_type_supports_border ) {
 			return true;
diff --git a/lib/block-supports/colors.php b/lib/block-supports/colors.php
index 6919f58c067e4..80a0a2cf974df 100644
--- a/lib/block-supports/colors.php
+++ b/lib/block-supports/colors.php
@@ -12,7 +12,7 @@
  */
 function gutenberg_register_colors_support( $block_type ) {
 	$color_support = false;
-	if ( property_exists( $block_type, 'supports' ) ) {
+	if ( $block_type instanceof WP_Block_Type ) {
 		$color_support = $block_type->supports['color'] ?? false;
 	}
 	$has_text_colors_support       = true === $color_support ||
diff --git a/lib/block-supports/typography.php b/lib/block-supports/typography.php
index 5c051ee05cc2c..3cda86cf0a257 100644
--- a/lib/block-supports/typography.php
+++ b/lib/block-supports/typography.php
@@ -11,7 +11,7 @@
  * @param WP_Block_Type $block_type Block Type.
  */
 function gutenberg_register_typography_support( $block_type ) {
-	if ( ! property_exists( $block_type, 'supports' ) ) {
+	if ( ! $block_type instanceof WP_Block_Type ) {
 		return;
 	}
 
@@ -76,7 +76,7 @@ function gutenberg_register_typography_support( $block_type ) {
  * @return array Typography CSS classes and inline styles.
  */
 function gutenberg_apply_typography_support( $block_type, $block_attributes ) {
-	if ( ! property_exists( $block_type, 'supports' ) ) {
+	if ( ! $block_type instanceof WP_Block_Type ) {
 		return array();
 	}
 
diff --git a/lib/class-wp-duotone-gutenberg.php b/lib/class-wp-duotone-gutenberg.php
index 270c13875787f..3395f98f09e7c 100644
--- a/lib/class-wp-duotone-gutenberg.php
+++ b/lib/class-wp-duotone-gutenberg.php
@@ -649,7 +649,7 @@ private static function get_global_styles_presets( $sources ) {
 	private static function get_selector( $block_name ) {
 		$block_type = WP_Block_Type_Registry::get_instance()->get_registered( $block_name );
 
-		if ( $block_type && property_exists( $block_type, 'supports' ) ) {
+		if ( $block_type && $block_type instanceof WP_Block_Type ) {
 			// Backwards compatibility with `supports.color.__experimentalDuotone`
 			// is provided via the `block_type_metadata_settings` filter. If
 			// `supports.filter.duotone` has not been set and the experimental
@@ -747,7 +747,7 @@ private static function enqueue_global_styles_preset( $filter_id, $duotone_selec
 	 */
 	public static function register_duotone_support( $block_type ) {
 		$has_duotone_support = false;
-		if ( property_exists( $block_type, 'supports' ) ) {
+		if ( $block_type instanceof WP_Block_Type ) {
 			// Previous `color.__experimentalDuotone` support flag is migrated
 			// to `filter.duotone` via `block_type_metadata_settings` filter.
 			$has_duotone_support = $block_type->supports['filter']['duotone'] ?? null;