Tacky Black Painters Touch

Hello :). I'm having a challange with the Painter's Touch 2x semi-gloss black that just refuses to dry and remains tacky.

My latest challange involved birch wood checker pieces, some sprayed with the gloss Apple Red and the others with the semi-gloss Black. Both got a light pass, then several minutes later a second spray.  Red dried fine, black is still tacky three days later. 

And this isn't the first time black has bedeviled me.  I hang all my work in a humidity controlled room so that's not the problem. And if my technique was wrong why do my other Painter's Touch colors dry with no problem?  I use other colors on a regular basis - although I did have a similar problem once with white. Hmmmm

Any ideas would be greatly appreciated. 

Thanks!