New Boss in Black Barya just disappeared

Same here.

Bug Report ID: #4.237.778.588

Bug reference number: 2 196 230 218
Encountered an issue with the Black Barya boss.

During the fight, the boss reached a phase and then disappeared completely.
The map shows "1 monster remaining", but the boss does not return.

This happened multiple times.
Map cannot be completed, boss loot lost.
Please investigate.

adding my experience to this as well, boss disappeared on me midfight