The Bug

If a cave spider spawner happens to be in a mineshaft section that a trial chamber replaces, the mineshaft gets replaced as expected, but the cave spider spawner remains, leaving an out-of-place spawner.

How To Reproduce

1. Start a new world in Java Edition 1.20.5 using this seed: 3057310577815726585 (with 1.21 Experiments enabled).
2. Run this command to teleport directly to the spawner once spawned into the world: 

   /tp @s 9 -27 304

1. Take note of whether a cave spider spawner is near you in the trial chamber. Also, note that the trial chamber replaced a mineshaft near the cave spider spawner.

Expected Behavior

As the rest of the mineshaft has been replaced by the trial chamber structure, the cave spider spawner would be replaced too.