Project access is cached until a reboot

Steps to reproduce:

As user1: Create a project
As user1: Set Default Project Access to: Read
As user2: Access the project
As user1: Set Default Project Access to: No Access
As user2: Access the project again

Expected behavior: When user2 tries to access the project after the default access has been changed back to no access, user2 should not be able to get in.

Actual behavior: User2 can continue to access the project until stash is rebooted.