I installed and activated the WPMU Dev Dashboard plugin, logged in to my WPMU account in the WP dashboard, and then added the site to my account in the WPMU. When I went back to my dashboard in WP, I wasn't able to access any page. Every page just redirected to /wp-admin/admin.php?page=wpmudev.
I finally had to go to SFTP and manually remove the plugin in order to access anything in the dashboard of my site. It looks like I have access to the Pro Features for the Smush plugin (which is why we purchased a WPMU plan), but why did that happen and how can I prevent that from happening again? We plan on using your plugins on our client's accounts as well, and we need to be able to have this work correctly and as intended.
I'm unable to grant you access to the site because as I said, I had to completely delete the plugin from the site in order to get anywhere in my dashboard at all.