Factorio Forums

I have item stackers set up throughout my base, and periodically one of them will stop producing. When I check to see what's going on, it's usually that my box is clogged with common quality items, despite the only grabber feeding the box being set to blacklist all common items.
Thus, I must conclude that the grabbers are grabbing common items at some point, though I haven't directly witnessed it happening. I'm open to other explanations as well.

Post a save showing the issue and add the version to the title please, see 3638.