I had the same problem, but instead of a block of redstone I had a normal block, which I powered. (The whole contraption was supposed to be a piston switch to a redstone wire. The piston came from underneath.) The piston worked, until I powered the line and the block above the piston was powered. Then the piston refused to go down again.
Elias Meyer
I had the same problem, but instead of a block of redstone I had a normal block, which I powered. (The whole contraption was supposed to be a piston switch to a redstone wire. The piston came from underneath.) The piston worked, until I powered the line and the block above the piston was powered. Then the piston refused to go down again.