Deleted/Off-limits/Ignored on merit history can be of some reasons:
1. You replied in a topic with low quality post but your reply has a Quality Post.
2. You have a Quality Post topic, with so many OT reply.
3. New forum guidelines can also be a factor. Like service merit are now being remove.
You cannot delete your own topic, only staff/moderators can do it. In terms of investigations for merit abuses, staff can still see their posts; we are just off-limits to see that board.