The Bug

Powering off a lever that is powering a piston, and then repowering it in the next redstone tick BUD-powers the piston.

How to Reproduce

Place down a sticky piston. Now, attach a lever on the back of the piston and extend it by flicking the lever. On the piston, put an L-shape of slime blocks on the piston - a slime block, a slime block below that, and then a slime block in front (relative to the piston) of that slime block. To finish, place a rail - any type - on top of the farthest slime block from the piston. With my testing, you can add whatever you want to what that piston is pushing (like a TNT duper). Just make sure you have that L-shape and rail. Now, flick the lever off, and then on as quickly as possible. If done correctly, the lever should be on, but the piston should not be extended. As per how BUD-powering works, updating the piston makes it realize it's powered and extend.