Finbar

These are not reaper bones minis. They came out of a DND board game. I am using reaper paints on them. The cracks appeared after drying.

Hi, started painting minis a few months ago. Started with the reaper learn to paint kit and have been enjoying myself immensely. Painted about 25 models at this point. A strange thing has started happening, odd cracks (see picture) https://imgur.com/a/O24oc have started appearing. These are primed miniatures. The paints have been thoroughly shook. I have tried doing more layers but the cracks still appear. What is causing this and how can I stop it? Thank you