My previous snippet to add reply titles was using an action hook after the reply was created to run wp_update_post, so it was not interfering with ASP. But I just found a somewhat hidden filter that runs immediately prior to wp_insert_post and was able to modify it to create a post_title, which is far better as it also doesn’t create a revision post. The problem with ASP has now gone away – so this killed two birds with one stone! Thanks very much for the prompt to look into this some more!
I suppose you can close the ticket now.