UPDATE: I've reduced the amount of thinner, which seems to have helped, and it does appear to be more of an issue with the chartruese than other colors. The weather was probably an issue also, was high 80's and very humid that day, may have had a negative effect. The thinner is very expensive thru CS so I make my own. Chemically it's just a mix of MIBK and Xylene that I put together for about $20 a gal.