Sculk shriekers gives you darkness effect only once per world
How to reproduce
Place a sculk shrieker.
Step on it to produce the vibrations
You will be affected with the darkness effect.
You won't be able to trigger the shrieker a second time therefore you won't get the darkness effect.
Expected result
Sculk shrieker should grant you the darkness effect every time you try to trigger it.
Observed results
Sculk shrieker only triggers and gives you the darkness effect once per world.
The team are currently aware that it is a bug: https://twitter.com/kingbdogz/status/1451275932770177032?s=20