Playing on the Nintendo Switch, and we've tried to beat this level twice. We arrive in the final arena for the boss fight, but the cutscene never triggers, just a giant health bar and no boss. We basically just move around and nothing happens. Tried backtracking to re-trigger it, and nothing. Today, on our second attempt, we noticed that standing against the far wall, the Anchor melee would inflict some damage, so the boss is way off to the side, out of our reach (possibly invisible?). It spawned an Elder Guardian, also off to the side of the platform and out of reach. No arrows or soul weapons or shockwaves or gravity will reach it/affect it. We reduced it's health until about 1/8 the total, but it had moved too far away to affect it further and we just gave up/quit.