Increasing the number of processes (max_processes) for a process_class has no effect

JobScheduler allows to change attribute max_processes of a process_class via the API. In this way it is possible to prevent more tasks of a job by setting max_processes=0.

But it is not possible to start tasks for those jobs by setting back max_processes to a value > 0. In this case the changed configuration of the process_class has no effect.