Using Dove Grey color with a more expensive paint sold at Home Depot (i.e. I specifically chose a nice 'line' of paint) and after doing my living room with two nice coats of this paint + primer, I can totally see the old light blue color on just one of the walls.

Why would this be? If anything, I feel like I used 2 very thick coats on the wall that shows the old color - which makes no sense. I guess I'll go for a third coat....just trying to understand why this may be.