Apparently when the lock is forced by an user, the first user who took the lock won't get a lock warning if they try to edit the page later.
- Edit Home page with UserA
- Edit Home page in-place with UserB: a lock warning is displayed, force it
- Refresh Home page with UserA, and try editing it again
- the lock warning is displayed again for UserA since UserB is editing it
- no lock warning anymore for UserA