Need help: Clement PDX tubular

Hi all. I'm in the process of gluing up new tires for CX season. Last Saturday I mounted up the new tires on the rims to stretch them out, no problema. Pumped them up and left them until yesterday (four days); I checked the tires each day and they were holding air, again no problema. Yesterday I took the tires off the rims and began the gluing process, pumping each tire a bit and putting a glue layer on the base tape. I set them aside to cure, and in a couple of hours one of the tires was completely flat. Pumped it again to be sure, same thing, flat after a few hours. The other tire is holding air perfectly. I know there is nothing I did while gluing to puncture the tire in any way, and it's weird that it would hold air for four days in the rim but lose it quickly off of it. Now I'm hesitant to finish gluing and mount it up.

Any thoughts? Has anyone seen this before? I find it strange that one tire will hold a small amount of air and the other won't. Is this $100 tire now just trash? They are Clement PDXs, if that makes any difference.

Thanks in advance,
-Colin