Phantom Canceled Registration!!

Hello, I looked for a topic about registration canceled automatically and I didn’t find it.
After the latest Tutor updates, some students are complaining that they can’t access a course, when I go to check I see that they have been unenrolled. I’m the only admin on the site and I don’t understand what’s going on. The strangest thing is that some students are enrolled in more than one course and are only unenrolled from one. This is happening on a recurring basis. Can anyone help me?

The page I need help with: [log in to see the link]