If we cannot load in-progress learning records on activities, how do we migrate data?

Summary:

We need to bulk load in-progress learning records on learning activities.

Content (required):

We are migrating data from a legacy LMS. Many learners are part way through completion of learning activities within courses/offerings. From what I have read and tried we cannot load a learning record using HDL against an activity. Can anyone suggest how to load this ongoing learning information into OLC?

Version (include the version you are using, if applicable):

22D