on the 4.2.0-130, after updating my survival from the 4.1.2-129, I manually dropped a stack of coal ore in the crusher, it broke 12 blocks and it stopped working, I threw myself to recover the ones that did not break and threw them again, but also only broke about 12 more blocks.

I apologize for my bad english
translated in google translator

Also experiencing this issue when manually dropping items in. Have noticed that feeding them in by Hopper seems to work fine.
Issue persists even after breaking/reforming the machine.

experiencing this exact same issue, i found a solution with a dropper with a redstone timer