The Auctions board is a different case, you can't even edit your post there (but as far as I know OP can move it to another board to sneakily edit posts).
Shouldn't a thread stop being self-moderated if it is moved to a different partition? Or does this only apply to those cases where the thread is moved to Meta?
Topics in
Auctions can't be self-moderated.
I just tested it: I created a topic in Auctions. As expected, I can't edit my post. I made a post from LoyceBot, that one couldn't be edited either.
Then I moved it to
off-topic, and normal edit features were restored. I edited my posts, moved it back to Auctions, and I cheated the no-edit-rule of the Auctions board. I still think this is a bug, just like it used to be possible to move self-moderated topics to a board that doesn't allow it. Theymos fixed that one years ago.