My friend Greg glued mine on, and he used canopy glue, just like he did on the windshields, but I have not had the glue softening problem, so like the guy said, maybe your glue was old. Could it be that your in a high humidity area, and it takes longer for the canopy glue to cure ?
I would not use CA to glue it on. When CA runs, it makes a real mess. I would just leave the turtledeck off until you can fresh canopy glue. Dennis