Total mesh deformation when in CAS

Hi. Your ring is big enough to be affected by more than b__L_Mid0__, so this is why it clips into the finger.
All CAS items should have a uv_1 map, which is what dictates how they will morph. All accessories should be painted with 007F00. Fingers and rings do not actually morph ( as far as I know ), so in this case it is not important, but still, this is something you should do and keep in mind.
Another thing you should keep in mind is the wireframe density and polycount. You want your mesh as low poly as you can get it without loosing details. There is no reason for a bend that is not even seen to be almost 2k alone, which is not much in general, but certainly too much for a ring. Say, if you were to make a necklace with the same density, it would probably go past 30k and affect game performance and loading time greatly.
Also, it's best to avoid n-gons ( the surface of the moon is an n-gon ). s4s will split it itself, but it will take its time. You can just use triangulate modifier to do this automatically.

You want the item you import in the package to have the same vertex groups as the original. When it is not the case, you or someone else using your cc might get distortions like this

Unfortunately, there is no ring that has all 3 vertex groups you need. So you can just risk and wait if someone reports distortions. Theoretically there should not be any, these are not the vertex groups that usually cause them, but just so you know. If you will get them, message me please
Here's a new blend, pls check it in CAS for I have no poses needed for this