This issue has been reported by NGC at ro.wp, and I also have encountered the issue at fr.wp: some of the mentees that appear in the list of recent changes under the "my mentees" filters aren't mentees assigned to the mentor's account.
- Filters used by NGC 54 at ro.wp
- Some mentees that are visible using the filters but who aren't assigned to them: Tudorrares111, AlexB15l, Constantin Dutchevici.
- My filter at fr.wp
- Some mentees that are visible using the filters but who aren't assigned to me: Lokotoro, Aayc03, LaMotte514
- I checked the 10 first mentees I have in my recent changes.
These users should only be visible to their mentors, not to other random mentors.