In some cases wp_get_post_parent_id() = get_post_ancestors

[chvon7thal]

Using wp_get_post_parent_id() while parsing gutenberg blocks in a save_post action, I found out, that when a parent page exists, and parent_id is the actual published post wp_get_post_parent_id() gives back the post_id of the parent page.

A turn around seems to be ($postParent == $postId) ? $post_current_ID : $postId;