Aren't your tyres directional? So were the tyres rolling the wrong way all that time?
No they're Asymmetrical(?), "outside" on the side wall.
I'm assuming there's uneven wear on the tyres, probably prior to the last set up where they got it cock on.
So say the camber is -1.20 left 1.10right "to counteract the road crown" as they call it, as the usual excuse for leaving it as is.

The tyres then wear to those settings to an extent. Then the wheels are swapped to opposite sides. There's then an element of excess camber in the tyres tread that don't match the settings on the car.
Would that account for it?

because sc3 are not directional tread pattern. So I guess that only leaves the pre existing wear already on the tread.
I did notice Micheldever where bet careful to mark which wheel went on which corner. Costco where not so thorough when they failed to rebalance the fronts. I only noticed the wheels where on the wrong side as one if centre caps was an odd one and was fitted pas side. I know that wheel was on the other side when new tyres where fitted.
Anyway, it's very much improved. Still pics up lines in the road but only just enough to be considered acceptable feedback in that it just lets you know it's there. It's more online with the life of the tyres now. Where as before they felt shagged reet oot.
Moral? If I'm right that is?

always fit the same tyre back on the same corner.