I have been experiencing this issue as well in 1.16.1. I know for sure the hives worked before I updated the server from 1.15.2 to 1.16.1, but I believe the hives weren't loaded in 1.16.1 before today. This issue happened to me once before, the first time I placed them in 1.15.2. That time a restart fixed the problem.
In the attachment, I have the last part of the server logs of today, of when I first loaded the hives. I also performed a /data get command on one of the misbehaving hives.
[media]Can confirm for 1.16.1 as well.
If the delay is changed to 2 or 4 ticks while the repeater is powered, it will remain on permenantly on if a 1-tick clock is powering it. If the delay is changed while te signal is off, it will behave as correctly, outputting 2/4 tick signals with a 2/4 tick off period in between.
If you are underneath a transparent block (such as a fence or a glass block), the POV gets moved upwards, but the suffocation still happens. This is missing in the description, but might be useful for anyone trying to find the actual cause of this bug.
I can still reproduce in 20w49a.
Also, I added a step by step reproduction guide to the description. Could you confirm wether your reproduction attempt did follow this newly added guide, Avoma?