Doesn't that just mean you cannot edit/delete the initial post that starts the topic? That has been the behaviour for as long as I can recall but I think the message is relatively new as I think. Might be wrong on this.....
Would I be correct in assuming that this message appears AFTER the new topic is posted? Obviously it didn't stop you from posting... I've seen such issues here before.
It is a warning given after the post is submitted. Here is a sceenshot from my test post:
There seams to be a lot more fields to fill in than there used to be. Is it exposing fields meant for internal use? Here is a snapshot: