Hey, this has to be a bug. I started a brand new unity scene, and just put in 2 spheres, and a box, and some area lights and the skybox with an HDR, as basic as you can get. I changed my objects to Static for baking, I’m using progressive baking. and I get this nasty seams. I’ve tried lowering and raising the indirect and direct resolutions, still got them nasty seams. I even just created a new scene entirely, drop in a sphere, and changed it to static, and boom, seams. Attached is an image of me 1 hr into changing all kinds of settings and seeing literally no change in the seams, not even a smidge of it POSSIBLY going away. This unity, is why people run to UE4. I’m trying to give this program a chance. But right out of the gate I am having Issues in baking your own built-in primitive shapes? Come on.
Try disabling the “Optimise Realtime UV” in the “UV Charting Control” of your object.
ps: Your screenshot resolution is pretty pointless. We can see the spheres but you can barely read anything else.