Error in creating round 3 in campaign #928

[CiellB]

The jury coordinator of #928 complains about not being able to create round 3. (And a non-descriptive error message)

What I observe is that in round 1 not all tasks were completed, but round 2 was created nevertheless.
In round 2 all tasks are completed, but they are unable to create round 3.

• please help the coordinator to set up round 3;
• please make sure new rounds cannot be created when there are open tasks in previous rounds;
• please make sure the error in round creation is descriptive.