Title is self-explanatory, but essentially sculk sensors will fail to detect Vibrations until the world is reloaded. This can be spotted when generating a new chunk that has a deep dark under it.

Interestingly enough this also seems to be the case with the initial spawn chunk as sculk sensors will fail to detect Vibrations in the spawn chunk until a world reload is performed.

Standing on sculk sensors directly will trigger them, but the vibrations will not be passed onto nearby sculk sensors or sculk shriekers, the latter can also still be triggered by standing ontop of it directly.