It uses and consumes items it shouldn't while auto-crafting, like iron buckets, and more from other mods, which makes auto crafting recipes using such items - useless.

The same bug is happening in the Project Bench.

Ye, hope this can be patched. I'm wasting iron on buckets xD

Attempted fix here cebd8b3
Reopen if its still an issue

Yes

I bet this is only for MC 1.xx right?

I've met it in 1.7.10, my pack stuck here because some other mods.

Yeah, it loses the byproducts and only outputs the crafted item.