users can't delete item, maybe lose elevated role

I have two sites set up nearly identically with the same roles having the same permissions. On one site without OG User Roles (and consequently OG Forums) enabled, it works fine. On the other with OG User Roles, my users can't delete their nodes. Everyone has a default role "parent" with read-only permissions. In their particular group, they are elevated to "instructor" where they can create and edit their own content. However, when they hit the delete button, instead of successfully loading the delete confirm page at node/$arg/delete, they are given an access denied error. I think what's happening is their role is being lost along the way and they are reset to the parent role. Any ideas? They need to be able to delete their own nodes.
~cindyr