Pistons are still extended when a block over them is activated.
1. Put down a sticky piston (facing to the sky)
2. Put a solid block on the top of it.
3. Activate the piston.
4. Activate the block with a repeater or anything.
5. Try to deactivate the piston. It'll not working.
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186th Duplicate of MC-108, please use the search function to see if your bug has already been submitted. Currently over 57% of tickets are being closed as duplicate.