I'm having trouble with managing permissions on a page . When I add a number of users, some seem to stay attached while others don't. When I try removing a user (adding the user again enables the trash bucket), again some stay removed while others do not. There is no difference in any of the users. Also, is there a limit to the number of users/groups that can belong to the CUG for a page?
I don't think there is a limit on number of users and number of CUG. Closed user groups (CUGs) should always be created with performance in mind. Although the number of users and groups in a CUG is not limited, a high number of CUGs on a page may slow down rendering performance.