I have tried multiple times to fight Lagon, which may be fixed for others, yet for the sentinel in multiplayer “smite” doesn’t target him unfortunately. Since the paladin build I have uses this skill for healing and mana regeneration as my primary attack, the boss is unplayable for me.
This problem also exists with the lightless arbor boss as I have just discovered. I am not sure why, but it seems the bosses that have their heads out of the top of the frame of the screen are bugged in this way. I haven’t had this issue against any other enemy yet.
The only way I have been able to kill the boss is with my brother doing the damage while I just buff him haha.