When you add any number of speed upgrades to the ore crusher, and put in ore, it destroys the ore, and nothing happens afterwards, no output, no progress, just ores lost forever.

Works fine without speed upgrades.

If I put a stack of ores in it tears through the stack of ores in a couple seconds, also destroying all of them.

I felt a video would best demonstrate this: http://share.coros.us/files/tinkerio-orecrusher.m4v

Using version: 1.12.2-rw2.7.1

The issue was solved in commit 516cc30. Thanks for report the issue.