An observer pushed by a (non-zero-tick) sticky piston releases a pulse when pushed, and does not release a pulse when pulled back. This behavior is (no longer?) the case for zero-ticked pistons, thereby breaking a commonly used pulse generator if the input is zero-ticked.

Steps to Reproduce:

• Place a sticky piston horizontally
• Place an observer facing it and redstone dust one block away from the obsever, so that it gets pulsed when the observer gets pushed
• Apply a zero-tick redstone signal to the sticky piston twice. The first time it'll pulse the dust as intended, and the second time it will also pulse (this is the bug)