Dungeon Spawner, No mob in spawner, chests are invisible

Found dungeon spawner - world was made in 1.11 and is likely spawner was spawned in 1.11 - I found a spawner with no chests and the spawner itself had no mob inside of it, i found the chests by walking into them, they were invisible but had the outline when i aimed at it. Once I opened the chests appeared but they were empty - I had never found this dungeon before.

I got a screenshot after I had found and opened the chests.
It was just a random dungeon in a survival world

UPDATE
Seed = -5510540371251330925