Knowing the process cycle would help a bit!
But, generally, coating defects appear perpendicular to the edge of the paper and not at an angle. Well, I take that back a bit. If the coating machine has a 45 degree turn around, then you can get defects at a 45 deg. angle as well. So, if they are manufacturing defects, I would guess right now that they arose later in the mfg. process. Maybe in cutting or packaging, IDK for sure, but this is my guess.
I cannot see an easy way to get this from the process, but the process cycle would help indeed if it is a process problem.
Oh, BTW, could you see this in the developer?