Steps to reproduce:
- As default user 'admin', create a user 'admin1', give him the Administrator role
- Log in as admin1
- As admin1, start the export of the default site
- Export process finishes normally
- As user admin, delete the user 'admin1' (first deactivate, then delete)
- As user admin, check the export process'. admin1 is not shown anymore under Processes, and Exception is thrown in the log.
Excepted behavior: Admin1's export processes are visible in the list
Actual behavior: Admin1's export process disappear from the list, Exceptions are thrown in the log.