Technician Roles & Permissions

When assigning multiple roles to a technician that includes different permissions within the same module, for example, I have two roles created. One role allows technicians to View Only All Requests. I have another role that allows technicians to View, Edit, & Add only those Requests assigned to him/her or their group. If I then assign both roles to a single technician, I would expect the technician to only be able to view, edit, add his/her assigned requests and any requests in his/her groups and only be able to view requests assigned to other technicians/groups. However, that technician is able to view, edit, & add ALL requests regardless of whether they are assigned to another technician or not. This is not how I would expect the permissions to apply.

Am I missing something? This appears to be a bug in how roles are nested inside a given module. Is there a way to get this type of permissioning to work in the current version?