In map seed 7466761204673980157, at X106, Y1, Z86 there is a spawner. However, there is no chest. I first went into this world in survival and found the room. Then, I tried the same seed in creative, and it's a problem there, too. I changed to spectator mode and looked around the area, but no chest.

There is a hole in the floor of the spawner room, which may have been constructed after the spawner room. It's possible the chest was in that corner and was obliterated by the addition of the air blocks. If so, this is a bug most likely related to Caves & Cliffs.