Just read the crack thing, I've experienced this twice, and I sat around for days on end trying to figure out what I did, and it turns out that that I went really, really thick on the paint on these lures, so that might be something for you to look into. I had let the lures dry inside on a rack for a few days, too lazy to clear them, I guess, so I'm not thinking it's the moisture, but still have not ruled it out, as the thicker the paint, the harder it would be for the moisture in the lower coats to dry.
Give Dean's method a try, see if that works better for you, the coating is excellent, high gloss, super strong and thinner than epoxy, might take a bait or two to get the hang of it, but before long you'll be on track.