Cannot cancel workflow when task assigned

1. install 9.10
2. login as Administrator
3. create 2 users (userA and userB)
4. create 1 document
5. set full rights both users
6. start parallel workflow as userB
7. assign task to userB
8. login as userB
9. observe userB sees the tasks
10. observe userB sees the cancel workflow button
11. click the button
12. observe nothing happens
13. try to cancel the workflow as initiator or Administrator and it works fine.

Latest HF installed -> same behavior.

Expected behavior: either the workflow should be cancelled or the button should not be shown