Abyss Valdo Failing - Bug 2320500719

I’ve been farming Valdo’s “Forbidden Swathe,” which grants Crown of the Tyrant. This Valdo modifier states that:

Area contains an additional Abyss
Abysses in Area spawn 200% increased Monsters
All Abysses in Area must be completed to claim Reward

I’ve run about 100 maps like this, and I’ve consistently failed in some of them, even though the Abyssal Trove appeared and the Bismuth Ore was collected.