[edit] Never mind, found and defeated the boss.
I did Coldharbour a while ago, but there were some delves I never completed, so I returned there today to complete them, except for one.
I've re-entered Cave of Trophies delve several times, even reloaded the game several times, but Gnilokelo is never spawning, so I can't complete the delve.
There's a 2016 thread about this same problem, which said that the game restart worked, but it's not working for me.
Edited by ZOS_Bill on June 2, 2022 5:15PM PC(Steam) / EU / play from Melbourne, Australia / avg ping 390