There was undoubtibly prep work that was not done properly for this to occur. I have been with SW for 10 years and never any problem.
Why has Behr filed chapter 11 and 13? Why do you see in home centers so much of Behr returned? Why do so many customers complain because of shaddows in corners and cut in areas? Why are so many family or sole prop hardware stores removing Behr from their merchandise mix? Why does Behr not remedy any customer problems with their forever guarentee and use the excuse of prep fault?
Most all wall paint especially flat will not stand up to scrubbing off stains and ect off walls, it is even mentioned that flat latex is not for this. If you have an area where you want and need to scrub frequently do to traffic and the such, you are recommended to use semi gloss or eggshell sheens. I bet if you used flat on your repainted walls and do the same scrubbing as you did with SW, your walls will do the same and possibly even more so.
Behr's main problem was shadowing and color distortation within the same area. you are no doubt one of the few customers that have had any success with this brand. I am glad for you.
However, due to its reputation and findings, I will push on with my campaign to lead customers away from this brand especially when they put their hard earned money and time into a painting job.