Mine does the same thing. I don't know if this will help, but here's what I've found.
I am running 285/40-18 in the rear (26.98" tall) and 255/35-18 in the rear (25.03" tall). Because of the different diameters it screws with my ABS since the wheels are at a different speed. When I first start out driving I have no ABS light and I can turn the traction control on and off. After driving a while, the ABS light comes on and when that happens I no longer have control of the traction control.
If you are running the same size tires but still experiencing this phenomenon, I would say you might have ABS modules going out. This is fairly common and the modules are cheap (less than $100).