I would like to add to this and managed to replicate the issue. I have a UDT Definition created that has a parent UDT defined. If i go and create a copy of a tag that comes from the parent UDT, rename it and reconfigure, when i save the tag, it accepts it without issues and propagates to all my instances. The moment I reboot the tag provider, the changes disappear. I tried checking the logs but they are not showing any errors.
If i create a new tag (instead of copying a tag from the parent UDT) and then copy this tag, i don’t have the issue. This is on 8.1.48