Mandatory Learning historical credit

Does the historical credit on mandatory learning only apply to the learner group that the learner is in when they complete the class? We have multiple learner groups set up for mandatory learning, and we have learners that will move around from one learner group to the next. I have noticed that even though I have applied the historical credit for all learner groups, people are still getting enrolled when they move to a new learner group after having already completed the class.

I wish the documentation on mandatory learning was more comprehensive, as I feel there are a lot of nuances with the program that are not published.