Retained logic Progress override in project scheduling?

Suppose you have two activities: predecessor activity (A) and successor (B) related with an FS (finish to start) relationship with no negative lag, for some reason things went out of the planned sequence, and activity (B) actually started before the finish date of activity (A).

Now, what happens to the remaining portion of activity (B) at the right side of the data date? ‘Retained logic’ and ‘Progress override’ are two different ways to answer this question. Considering the mentioned example, ‘Retained logic’ approach suggests that even though the actual activity duration (the part of the activity that has already passed) has gone out of sequence, the remaining part shouldn’t do so, and it must “commit to the relationship” by not starting before its predecessors no matter what. That means the activity is split into two parts (durations) with suspension period in between.

On the other hand, ‘Progress override’ approach does not respect the logic when activities progress out of sequence. If activity (A) started before its predecessor (B) finishes, it should progress normally and the sequence logic (FS relationship) should be neglected.