Activity completion not transferring

Summary:

We have learning activities/pieces of content that sit across multiple offerings. We were told (and have tested successfully in the past) that if the same activity is used in multiple offerings and the learner completes it in one location, it will mark them as complete in all offerings this sits.

We've just had a situation where we've created a new offering and majority of the activities are the same except for a few. We've withdrawn learners from the old offering and enrolled them in the new with the assumption it would automatically transfer the completion of activities that were previously completed and have remained the same in the new offering. This is the behaviour that has happened for 2 of the activities but for the other activities they completed they're not transferring over and I believe should be. Does anyone have any experience with this and examples of why this