Hey Diz,
So I created an issue with the Dev team about this and hopefully at some they can find time to work on this. Whenever they have any update about if/when they will work on this I'll update you here.
Though as Levi pointed out:
Work around
- Add the content directly in the UID field and it won't change.
Alternatively
There may be a couple of steps that can lock your UID in place so that it's not overwritten:
- Add content to the field you wish to auto-populate the UID
- Either (click save) OR (go to the UID field and add then remove a space)
Hopefully this small process can help your case for the time being.
Let me know if it works.