I have 2 sets(10 doors each) of kitchen cabinet doors I have painted white about 4 weeks apart. First set came out perfect along with cabinet carcasses, the other after about a week, the color is way way off white. Both sets were primed with same can of Zinsser Cover Stain Oil based primer. Paint is Sherwin Williams Industial Alyd Enamal and sprayed with an HVLP sprayer. I used Naphtha to thin the paint and used exact same ratios during painting and I got vastly different results. Paint can was sealed so I know it didn't get contaminated and was well mixed with power paint mixer for second set. I'm at a complete lose! The only thing I can think of is the paint has a very limited shelf life after opening. Any ideas? thx.