Failed to join instance because: You cannot rejoin this area after dying (Burning monolith diff 0)

After spending a whole week searching for the fragment required to access the Burning Monolith, I finally made it to the map. During the boss fight, I died once, which normally shouldn't be an issue since it's a Tier 0 encounter and I should be allowed to re-enter the boss arena.

However, due to a bug, I couldn’t get back into the map, effectively locking me out of the fight. All the effort and time spent farming the fragment was completely wasted. This is extremely frustrating, especially given the time investment and the fact that the mechanic is supposed to be more forgiving at this difficulty.