Delirium Boss arena Bug

I don't know what information is needed so i am going to state as much as i can. Also i don't know if this is a known Bug

So i started a Delirium in a tier 12 vaal orbed map. I ran through the map straight to the delirium boss. As the boss fight started, the timer for the league started to tick down aswell. Now i don't know if i killed the boss just as the timer went to 0:00, but the drops from the league dropped more or less at the same time as the boss was killed. Now i am trapped in the boss arena and i cant get out of the arena to finish the map. I can attack monster which are outside of the arena though.