after the issues regarding the Darkmoon Decks (see this thread: Darkmoon Deck: Immortality Issue) have been resolved, I just noticed the exact same behaviour on my Demonsteel Helm Of The Peerless. My helm is upgraded with Obliterum 10/10 (so it has iLvl 900). BiB now wants to exchange it with the same helmet, but upgraded with PRIMAL Obliterum 10/10, resulting in an iLvl of - and here it gets really strange - 885. The end result is that my BiB DPS even goes down by a small percentage!
I think this bug affects all crafted gear that’s been Obliterum-upgraded…
The issue you have linked to hasn’t been resolved yet.
Yellow tried to fix it before he went on vacation but downloading the data didn’t work. Blizzard changed the bonus ID’s on crafted items so it’s resulting in weird behavior. Unfortunately, we’ll have to wait until Yellow gets back for this issue to get solved.