when i right-clicked a piston by accident, when it was on a clock, it shortly became invisible. that went me crazy and i wanted to try it again, and it did it again.

how to reproduce:
make an observer face to a piston(facing up).
connect a redstone line from the observer to the piston.
replace the piston. that creates a superfast clock.
now, hold right click on the bottom part of the piston (so not the piston head)
and, if you are lucky, it does it!
(if it doesn't, just retry or spam right click instead of holding it)

pleasse check the screenshots, i worked hard for one on the moment when it disappears.