Bulk functionality in Access Rights module request behaves differently from a single user request
1) Modify function is not available for permissions already existing for selected users, though configured on bulk execution plan.
2) For existing permissions, both add and remove are available. Expecting only remove not add because the permission is already existing for the selected users.
Single-user requests works as expected
Release : Vapp Identity Portal 14.3 CP2
In Bulk case, the modify option won't appear. The reason for that is because that in the Bulk case, the IP won't check actual permissions due to performance reason.
Example: if you try to assign Role1 and Role2 to user1 and user2. The IP won't check whether user1 and user2 already have Role1 and Role2 assigned. So modify option is not there. The same logic applies to add button.
Single and bulk request work in a different ways. This is the expected behavior