If a redstone device (piston, sticky piston, button, pressure plate, lever) is activated in the on position and you destroy it while it is on, it will drop as a block which you can then pick up. However, this is in creative mode, where the block should simply be destroyed and disappear.
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Comments
kumasasa
Well, I'll be darned. Someone did indeed already report this bug, multiple times too!
Duplicate of MC-149 - Please use the search function to see if your bug has already been submitted. Currently 25% of tickets are being closed as duplicate.