Sticky piston staying on.

This issue happens to me too with a regular piston.

I did a simple redstone clock with 4 repeaters and it worked as intended, but when i added another one the piston no longer retreats, even if i broke the redstone circuit, i does after a block update next to it. (the repeaters where at 4 ticks, the observer was just to start the clock)

Does MC-151418 describe your issue?

From what I understand of your problem, it works as intended

Look up "Quasi Connectivity"

Looking at the screenshots, yes, that's what happens. Duplicate of MC-108.