A Hopper under a metal former will pull out the iron from the input slot that a hopper above is putting in, so automating with non-intelligent item routing methods is not very possible. I believe this is an issue with I-Sided implementations, but I'm not sure on that. I'm guessing the imag fusor will have the same issue.

Will fix.

Also, pipes (and hoppers) can input items into the output once the input fills up, which is probably the same issue.