When generating new chunks, an error often occurs in which a geode with amethysts appears inside the trial chambers. Of the 5 halls found in the world, in 2 a geode appeared in the middle of the room.

Also, while conducting tests, I determined that this happens when approaching new chunks, and not when teleporting (At least from 5-6 attempts with teleportation, nothing appeared. However, when teleporting 300 blocks away from a place with an error, approaching and manual descent to the place, the bug was repeated twice. All tests were carried out on the same world seed.

Seed: 778650878593905782