Gen 2 KYB rear strut assembly defective spring straight out of the box. TWICE. Common?

I ordered all 4 KYB strut assemblies (SR4514, SR4513, SR4224, SR4223) from rockauto for my 09.
With the first set of new KYB rears the back of the car sat way too low. Top of tire was hidden by fender.
Ordered 2nd set of rears and the same problem again.
With the old struts that came with the car the ride height was fine.
Ride height with the new KYB fronts looks normal.
The strut asseblies and boxes looked fine and had KYB stampings and labels.
The boxes and strut asseblies looked new, so I don't suspect that rockauto had been victim of some kind of return scam and odds of that happening twice should eliminte this possibility.
The spring determines the ride height, so the spring must be defective. All 4 rears.
I thought KYB is supposed to be the best?
Is this common?