Hey there @spectrum, would you mind opening a separate Support topic with some further details including
- Some logs (like the first post in this topic).
- Links to the relevant posts on Discourse and Drupal if possible.
Not all 422 errors are the same. In the above case it was likely due to the content of the post.
*Note that I moved your post to Support from Support > WordPress as this is not about Wordpress or the WP Discourse plugin.