the users on my site are having an issue with logging

Hello, the users on my site are having an issue with logging in since activating this plugin.

Here's how it happens:

- The user signs in through the home page of the main site.
- They then visit a subsite
- The user goes into the admin menu, does different things
- The user logs out
- Now upon trying to log in, through the subsite this time, the user is prompted to sign up (through coursepress's courses-signup) for a new account after entering their valid credentials. Disabling Courspress just makes the default login window redirect to itself to re-attempt a login.

I have eliminated this issue down to this plugin. I have tested it with the Twenty Sixteen theme, and with other plugins disabled. Clearing cookies solves the issue, as does logging in from a different browser/incognito window. My host uses HHVM with an nginx fallback, so I don't think this is an htaccess issue.

Thanks for your help!