Lantern of Arimor - Tier of haunted modifier bugged

There is a bug where a haunted mofidier should gain a level or stay the same tier if it's already max, but in that case, it lose 2 level.

So the first image is the default setup I got.
https://imgur.com/a/U1Jeaid


The second image where the bug is happening. So I swap unaffected by curses with always poison on hit.
https://imgur.com/a/93tMVtP


But this is the only modifiers that does this. The other modifiers do not lose 2 levels and devoted either.
https://imgur.com/a/HtUgXWR