Epoxy still sticky after 48 hours

I’m having some issues with trying to apply a top coat on too of an repair. I have been using pro glass 1200 from fiberlay with 4:1 hardener. After waiting a while for the first part of the repair to cure I was on vacation so have no idea how long it took. But when I returned 2 weeks later it was good, I assumed I mixed wrong so this time I used a scale but didn’t take into account the density differences. I have tried to speed up the process by putting the board in a hot car. The weird part is the rest of the batch is perfect, not tacky or sticky where as the thin coat on the boards are still very still and can be peeled off in places where it went over glossy board. I have it a good rough sand and mixed a 10g hardener with 40 grams laminating resin I believe. I was thinking that maybe after I sand it a but it will be fine but with such a thin layer I worry it will all come off but I guess that’s ok too and maybe it will help seal it. And experience with sticky epoxy. Temps have been pretty high 70-90