I've seen a lot of confusion that its a systemic problem

United found loose fasteners in a different locations on each of the five aircraft they found loose fasteners on. This is right on the heels of another emergency AD for the MAX about loose fasteners in a completely different location. That definitely hints at a systemic problem.

If you expand the scope a bit, Boeing's had nasty assembly and manufacturing problems across its whole model lineup. I highly doubt this is a one off problem.