I'm having this problem. I'm using mixed lightning, and every time I bake the lightmaps, and press play to test the game the baked lightmaps turn back to black, even the lightprobes. I've seem some people say to uncheck the autobake option, and I tryied that and it didn't solve the problem. I'm also no using any kind of script to load my scene. It's just a lightning and graphics test scene and is strictly played via editor. I'm using unity 2018.3.2 and the HDRP. Anyone having the same problem, or able to give me a hand on this manner.