Looks like they fixed this in the update but for those of you that haven't had chance to install the update I've done the following:
Ends up this happens because there is no role set for the user in the DB for slack imported users. I was able to fix it with the following command in Postgres:
update users set roles = 'system_user' where email != 'admin@yourdomain.com';
Make sure to update admin@yourdomain.com with the correct email for your system admin account.
ALSO MAKE SURE TO BACKUP YOUR DB FIRST!!
-Wes