Defeated Wotan the Invincible > game bugs out and doesn't acknowledge it

So I solo’d Wotan just this moment and the game bugs out by not ticking the box to complete the Maliwan Takedown. Despite the fact that the legs, the better half and the brain have all been obliterated, there’s still a red skull icon on the mini-map and when I throw my Hex grenades to track anything, they just loop around this invisible thing for quite a while. If I had to guess, I think that’s where the better half was destroyed and perhaps the game didn’t register it. Lorelei didn’t congratulate me after I destroyed the legs either.