course: closing editor while projects configure causes an exception

[haraldschilly]

in my dev project, when I open a course with about 100 students and that mechanism to configure all projects starts, I almost immediately close it. That way I trigger an exception here:

originating via

[novoselt]

Should it be visible in the developer console in the browser? I've opened a large course and quickly closed it without getting any exceptions, while that rapid counter was still going.