The SD footage – is it filmed? that is 24fps with pulldown? or is it 60field video-style footage?
The thing to do is pulldown removal on the SD footage so it’s 24fps, plop it in the timeline and it’ll look fine.
graphics at 23.98.
I don’t know how the BM card does it, but Kona outputs 59.94 from a 23.98 timeline very cleanly.