Tanking 25m Normal Cho'Gall - Unusual Fixate?

Something unusual happened during 25m normal Cho’Gall. I’m wondering if anyone has ever experienced this while tanking.

After the other tank taunted for 100% threat while I’m at 80% threat, the boss remained fixated on me during Divine Shield and BoP while the other tank remained at 100% threat. My corruption bar appeared around 1/3 or less.

Not sure what caused that? I basically had to sit there one tanking it trying not to press anything while seeing his name plate on the other tank at 100% threat but I’m still being fixated by the boss.

Basically I ended up having to 1 tank the fight with like 5 stacks lol?

never had that happen, what is your tank class? and are you using a threat addon to track? if you out threat the tank taunting, he will turn right back for you. and target change normally happens at like 104%+. however, if its staying on you during the bop without a taunt that sounds like a bug.