Steps to reproduce:
1. Create 2 users, user1 and user2. Create a group with all ROLE_UI permissions and a ROLE_CAPTURE_AGENT_* permission so that both users can schedule events, with both user1 and user2 as members.
2. Login as user1, schedule an event, default ACL so only user1 has
read/write permissions in the ACL.
3. Login as user2, attempt to schedule an event at the same time.
4. Login as admin, attempt the same operation.
When scheduling as user2, the conflict check fails with associated errors logs in the opencast.log file. A non-specific error is shown to the user at the very end of the process ("Cannot create event").
As admin, a conflict error and details are shown immediately.
Conflict details should be shown as for admin.
Workaround (if any):