Redirected mail directory home deletes folder on logout

I have a network home user account that has it's ~/library/mail/ directory redirected to /tmp/<username>/library/mail/ on login. However every time i log out and back in again it's deleted all the data in that mail directory apart from the MailData directory. This means that when i restart my mail app has no accounts even though they all still appear in internet accounts under system preferences but with mail unchecked. Reselecting mail on each makes it work again, but then it has to redownload all the mail in the account.

My workgroup manager has this in the user group's preferences

The caches redirect seems to work fine.