Blocks of some layers disappear after exporting
So sometimes, not all the time, when I export a drawing, random squares of some of the layers will disappear. It's not because of the selection tool. The image is totally fine until I export it, and I've exported it as a PNG and a JPG and the problem persists. I have no idea how to fix this and need help. In the case of the second drawing, it even lightened the pants and didn't erase the layer at all. 

