Delirum boss killed no drops. ended up the town portal is open, exit and enter gives Wave 16/15

hello, you can advice on this ? Spent hours to collect that splinter drops 1 by 1. Ended up unable to get the rewards.

And boss is killed but the drops didnt appear, yet the town portal appears. Exit and enter gives me ....


Wave 16 of 15.

Please return me the delirum orb for this bug.