I got the same problem with my posts and comments. They were flagged, which was obvious for me after i activated the "showdead" option in my profile, or they got marked as "shadow-dead" and I only found out via the public JSON API. "Shadow-Dead" means, for me, everything looked okay, but no one else saw my post.

After that, I asked an HN Mod what the problem was, and they thought my posts were created by GenAI, and because of that, they were flagged. And he gave me the advice that I don't use GenAI at all for HN, not even to polish my crappy text.

Hope this was helpful, wish you a good Day