As I understand it, the board found the discrepancies troubling in 2018 as well. Figuring out why these discrepancies, if they differ from other parts of the state, are occurring is perfectly reasonable. I don't mean that the election shouldn't be certified because of these discrepancies but that they are a problem that ought to be fixed rather than ignored.
What I say above depends, of course, on whether such discrepancies are normal and expected. From what I understand, there are more districts failing to balance in Wayne County than elsewhere. Seems reasonable to try and understand why.