Hey @nguyenhuyquang and all 
, just following up on this. I was able to work with some folks internally. Currently, this is expected behaviour as split lines are for the moment, only created as visible when BOGO discounts are applied.
That said, I definitely understand that this isn’t ideal, so I’m logging a feature request on my end for you too. If you’d like me to include any use cases/notes in the feature request, just let me know here and I’d be happy to include those.