What you have is shrinkage of the adhesives in all aspects of the build. What I used to do back in the day when I was building models that were glassed is this. First off use 1.5 ounce glass cloth. It gives you a more solid foundation for the finish over time. Next once the model is glassed you need to cure the resin for at least 30 days in a hot situation, and not the sun! Better to lock it in your car with th windows up for a month. It is like an oven and will fully cure the resin over the 30 days and handle most of the shrinkage. Next once you are primed and ready for paint, do it again. The primer shrinks! You will find all of this when you look at the model during these curing periods. It is very common to see more of this on gloss paint schemes.