Every time I fight the hydra, I fight the Ebon head, then the 3 colored heads, and the Ebon head returns. But, I'm unable to hit him, for his icon doesn't show up on the tiles. This happens literally every time I fight the hydra. Is this currently being fixed? I would like to be able to continue the main quest.
I ran into this tonight, and I think I have figured out what triggers this bug.
1. The first time the Ebon is damaged enough to sink, the following round the goal changes to defeating one head of each color.
2. Once you finish the third of these goals, the Ebonimmediatelypops back up (instead of reappearing at the end of the round, like the rest of the respawning heads).
3. If, once it resurfaces, you damage the Ebon through Epics or AOEs in the same round as it first reappeared, then it sinks again without resetting the goal back to killing one each of the other three heads.
4. The next round there is no Ebon head and there are no new fight goals; the battle is now stuck with no way to advance it.