Copper Citadel - Last boss unexpected error

Got this super annoying bug 2 times in a row at different Copper Citadels at the exact same time. Game freezes just when the boss is about to die (second stage) and you get something like ”unexpected error” and taken back to login screen and when logging in you go to your hideout.

Most annoying by this is that you get a failed Citadel when you were seconds to beat it.

No way I’m spending hours and hours more to find another citadel until this is confirmed fixed!