OK so I was building a mob arena for my server using command blocks to teleport you to the arena, when all of a sudden, the button stops working. I check to see what is wrong, and normal redstone is keeping itself powered on. Just normal redstone, no torches or repeaters. (That or the button/pressure plates are getting jammed.)
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Steps to reproduce:

Step 1: Create a small redstone connection to power a command block that teleports you anywhere.

Step 2: Use the device, whether it be a pressure plate or button, they will get jammed... you can't step on them or press them, and the redstone will self power itself.