FIORI ESS MSS Overtime quota request: no details in Inbox for request

Hi community,

I implemented "My overtime requests" (App-ID F4939) and "Approve Overtime requests" (App-ID F4937). First app works just fine. Workflow starts, workitem for manager is created. Manager finds the workitem in his Inbox. The problem: he does not see details for the request in the inbox (as for the absence request, he can see details). Also Button "Open task" does not work. A new tab opens but screen is empty.

Please have a look at the screenshots: https://drive.google.com/file/d/1-dcmRRSgdgBtFdgV_D0um4aNk4WSINb_/view?usp=share_link

Thanks for any help.

Best regards

Chris