Thanks to all who responded to my questions regarding white residues in conformal coating. 

Just an update:  To prove beyond a doubt that the issue was caused by humidity a small sample of the assemblies were sprayed and then put into an air conditioned room to dry.  Those samples look great.  Now on to discuss why the supplier didn't know this would be an issue and didn't control their process.  

I guess I will get out of the office for awhile.  

Kathy