Note: I only tested this bug in 1.21.0 but when i entered it for the affected versions, it said that 1.21.0 does not exist. So I do not know if this bug happens in 1.21.1.

I was in a creative testing world serching for trial chambers. I used "/locate" to find one. But when i tried triggering the trial spawners by turning my self in to survival, they did not spawn. I even tried to reveal my self to the spawner in survival as shown in the video. I don't know if it also happens in survival only worlds but it is kind of annoying. To recreate, just fly into a naturally generated trial chamber and go into survival, you can then explore the entire trial chamber without one trial spawner triggering.

(P.S. Ignore the fact that the video attached does not have audio)