Hi, I found an issue with backWPup and bbPress where site roles, backWPup roles and forum roles get mingled up.
See my topic at bbPress where I explain my findings.
In short, installing bbPress after backWPup makes the admin installing the plugin the only admin, other admins lose their role. There is also a mixup of the roles of backWPup, bbPress and Wordpress.
Installing the other way around everything stays fine. But after deactivating BackWPup the corresponding roles are listed under site roles.