For courses containing large numbers of users with different roles it's desirable to filter out roles as well as groups of users when searching the enrolled users list. In the case that I encountered this issue, we have 'revision students' with viewing rights (who studied the topic last year but need access to the content) as well as 'students' taking the course this year. If you apply both a role filter and a group filter, when you click to move to the next page (if the list is longer than one page) the group filter is removed (but the role filter remains).
The expected result is that all filters that are applied should remain in place between pages until actively removed.
Thanks, Gordon.