Portcullis used to work with a set up of two sticky pistons stacked vertically with a regular piston. On top are two gravel blocks. Used to work prior to update. Now after pistons push up gate (using the two gravel blocks), the pistons retract.  As soon as the gravel drops on it, they break.  This happens with multiple units stacked. When two blocks are on one regular piston, they drop fine.