Utzaal Checkpoint Warp bug

If you leave one of the "treasure rooms", activate the checkpoint, and die all more or less during the same time, after having discovered the area boss, there's a chance you'll get warped to a "treasure room" checkpoint after said boss. The entire area is accessible, except for the level transition betwen Utzaal and Aggorat, which seems to only unlock after killing the boss.

I have encountered this same bug. I activated the checkpoint outside the first treasure room, went inside to collect the treasure, left the treasure room and got obliterated soon after. When I respawned, I was outside the second treasure room.

As the OP mentioned, the entire second half of the map is explorable. I even got a quest update when approaching the exit to the next area, though no transition was visible, which confused me. Wandered my way into the boss fight from the wrong direction and was subsequently shown how unprepared I was for the fight.

When defeated, I respawned at the checkpoint just before the fight.