Arbiter of Ash BUG

Went into Arbiter of Ash with my buddy after hours of grinding to find and complete citadels. he died to a 1 shot mechanic and i was killed shortly after. Upon pressing respawn with it saying 5 attempts remaining, i was brought back to my stronghold and not allowed to enter the portal to fight him again. HOURS lost.

after googling to see if others had a similar issue, it seems going in co-op has some sort of bug to not allow retries? why doesn't it say that? maybe before entering and feeling like the game stole days of progress and hours of regrinding to fins the same strongholds to retry.... i understand having to fight it multiple times to get all the skill points, but this was a huge dissatisfaction to feel relief that we could retry, only to get kicked back to the stronghold and told i cant re enter due to already dying in this instance.

people that had this happen should get the keys refunded. they cost more than ive seen in this game to rebuy and grinding them again just for another "first attempt" feels pointless.