me and my friend have a cobblestone generator with pistons pushing the cobble up but somtimes when server saves the pistons stop working and when you place a block on them they dissapear, they also dissapear when you mine them. they dont drop the piston and other pistons cant push them. when you mine them the "arm"(the extended part of the piston) part is left where the pistons should have been
Hmm, I had a similar bug on TPPI once. No idea where it comes from though. A Co-Admin or Admin should be able to clean it up using creative mode, so please create a ticket at the location so we can find it. Apart from that this bug needs investigation.
i can clean it myself i just lose the pistons once sometimes i just make a block update and puff its gone