[UI5 BPM-Task 403 Forbidden] Combination BPM OData and UI5 Task produces error

Hello,

I have developed a UI5 task for a BPM process but there is a confused error: 403 Forbidden.

To the workflow:

1. the BPM Task runs
2. the token enters the UI5 task with no problems and the task is shown with data of process.
3. then the user completes the task by pressing the button, the 403-Forbidden error is thrown

But why? 😕

https://help.sap.com/saphelp_nw73ehp1/helpdata/en/f5/4193ee8dd44569b1dbee8c7a8271f4/content.htm

This link does not help. All roles are assigned to TaskProcessor role and this role to each user.

If the user has no permissions to work with data, the 403 would be thrown at beginning while entering.

But there is no error. In response, there is no "x-csrf-token" in header, so I add it manually by claiming.

Thanks for replies in advance.