In creative. Currently in Realms. After time sticky pistons in two areas stop working. You can break an invisible block in front of the sticky piston & it works again.
I have tried all kinds of solutions including re-building & the sticky pistons function for a little while. Sticky pistons with the exact configuration nearby do not have the bug.
It seems to create a ghost block.

One configuration is 3 vertically stacked to open "a door". The opposing 3 stacked Pistons always work. All three of the buggy pistons create the ghost block. They are activated by stone pressure plates. Either pressure plate activates all 6 pistons opening the "door". 3 pistons always work, 3 stop working after leaving Realms for a little while.