Used a sticky piston to hold a chiseled stone block as a 1x2 door, used to teleport player once opened. found if a sign was behind the top chiseled block the sticky piston will fail to retract despite power input.
As shown in screenshots provided:
Screenshot 1: closed doorway, both top and bottom piston powered, and a sign is behind the top block in the doorway/
Screenshot 2: bugged opening, both pistons have no power yet the top piston wont pull back.
Screenshot 3: correct opening, both pistons have no power and no sign behind top sign.
This ticket is invalid as it relates to a modded or 3rd party client/server.
Any non-standard client/server build needs to be taken up with the appropriate team, not Mojang.
Any plugin issues need to be addressed to the plugin creator.
This site is for addressing issues related to the base unmodded MineCraft.