As mentioned by @Holmesware This solution conflicts with local user permissions, I kindly ask that you modify your solution. I don't know which ranges are the best, this may vary per user, and I don't know what ranges are used exactly by Unraid but i think the following values are safe
So your config would look something like this:
When you create local unraid users, it maps those users starting from 1000, that I know for certain.
You can also check the id for any user (active directory or local) by the id command in the unraid terminal
Example: "id [username/groupname]"
Edit:
I only now realized you corrected yourself, I mistakenly read your solution as ready and therefore implemented it myself, without reading any after-marks. Should've read completely the first time around