I have a problem with some spray cans of Underhood Black. In the past, I bought a couple of cans off and on and on occasion, one of the cans dried with a white fog on the surface that was painted. I had to sand it down and finish with another can that has been previously used. I thought I just did some prep work wrong. Just recently, I purchased 4 cans to repaint the underside of my car hood. When I got to the 3rd can, it dried with the same blotches of white. Fortunately, I was able to finish with the 2nd can. The 4th can is unused, as I cannot trust it. Has anyone had this problem? My technique for prepping is the same, and I should point out that the cans were the same temp as the hood. Temp was approx. 75 degrees, humidity unknown. Thanks for any insight. Frank.