Siege boss spawned by Maven prevents rituals from activating

Reference number: 1,672,639,716

When the Maven summons the Siege map boss and gets killed inside a ritual that has not been activated yet, it cannot be activated unless I detonate the corpse of the boss. This has happened to me twice with the same result. I have recorded a short video to show proof.

https://www.youtube.com/watch?v=i9LA07z4lLA