Seed: 128891900971611559 (Large Biomes)
Coordinates: 2396 -11 -1528 (spawner, chest next to it contains vault loot)

In short, inside my Trial Chambers i found Dungeon (Monster room) with 3 chests. One of them (closest to spawner) generated with Trident, Ominous Bottle and Honey Bottle. Tridents cannot be found inside Dungeon (Monster room) chest loot, so I'm guessing that somehow Vault was overridden by Dungeon and its loot was placed in chest.

This bug is possibly related to MC-266434.