"Required course" not working

Hi. I have a site with Opigno 1.43. I have configured two semi-public courses: Course 1 has one "Lesson required for validation". Course 2 has Course 1 as "Required course". However, when a user who is enrolled in Course 1 passes the lesson required for validation, Course 2 continues unavailable for that user. The behaviour I would expect (and wish!!) is that once Course 1 is passed, then Course 2 is available. Is this configuration wrong? Might it be a bug? I've checked the rule that controls this but I can't find the problem, if any. Thanks for your support! David