Heorot frequently charges into crevices, against walls, and even clips into the landscape during his Age of Winter fight. This essentially forces melee to facetank his damage and/or removes the ability to attack him at all due to his hitbox being obstructed or out of reach. I can provide screenshots, but I’d rather not create a third-party account to do so.
Also, I don’t have screenshots, but his spear attack telegraph sometimes doesn’t match the actual attack. I thought this might be intentional, though.