Our students just lost their access to the bbb rooms after updated Moodle to version 4.0.

When they try to click at the BBB activity just get the error message: "Exception - Return value of mod_bigbluebuttonbn\local\helpers\roles::get_role() must be an instance of stdClass, none returned".

They cant see the access to the rooms or any list of recordings.

This issue is related to group options at the course. When we set the options to use groups that error just show up. When set to "No groups" our students back to access the activity.

 If roles are no longer found (e.g by deletion) then a null is returned, which triggers this error.

Another ticket MDL-75693 has been opened that deals with the fact that roles are not able to be modified after being assigned (specifically from BBB activity settings)