Yet another piston bug

Piston bug. Rather than documenting it, I hope you don't mind a 55 second youtube video. https://www.youtube.com/watch?v=V1wnXWGwcc4

I got another example. It happens on both 1 and 0 tick delays, it seems.
https://www.youtube.com/watch?v=Kam-8QCi3Lo

Sorry if this is a clone, just there are so many issues out there it's nearly impossible to know.