diff --git a/.changeset/wild-seas-buy.md b/.changeset/wild-seas-buy.md
new file mode 100644
index 00000000..d10ecdc2
--- /dev/null
+++ b/.changeset/wild-seas-buy.md
@@ -0,0 +1,5 @@
+---
+"@wpengine/wp-graphql-content-blocks": patch
+---
+
+fix: Don't overload `NodeWithEditorBlocks.flat` on implementing Interfaces.
diff --git a/includes/Type/InterfaceType/PostTypeBlockInterface.php b/includes/Type/InterfaceType/PostTypeBlockInterface.php
index 965800bd..b5da76e7 100644
--- a/includes/Type/InterfaceType/PostTypeBlockInterface.php
+++ b/includes/Type/InterfaceType/PostTypeBlockInterface.php
@@ -62,12 +62,6 @@ public static function register_type( string $post_type, array $block_names = []
 						'type'        => [
 							'list_of' => ucfirst( $post_type ) . 'EditorBlock',
 						],
-						'args'        => [
-							'flat' => [
-								'description' => __( 'Returns the list of blocks as a flat list if true', 'wp-graphql-content-blocks' ),
-								'type'        => 'Boolean',
-							],
-						],
 						'description' => sprintf(
 							// translators: %s is the post type.
 							__( 'List of %s editor blocks', 'wp-graphql-content-blocks' ),