Ah! Thank you so much!
I did the blacklist thing after searching the github to see if someone else had the same issue, and came across the thread listing the minetweaker blacklist stuff. Adding it and testing it, it seemed to work on my end, but what I'm guessing is I didn't test the conditions properly that triggered it for other folks, which is definitely my fault.
Again, thank you for the update and explanation! =)
Not sure if it makes any difference, but my drawers were attached to a drawer controller when the issue occurred and I inserted the iron ingots straight into the compacting drawer.