Quicktime Player X Frame numbers instead of Timecode

Hi. If I click on Timecode in QTPlayerX it will toggle between Frames and Timecode. But it has been very inconsistent. Sometimes it works and sometimes it doesn't. Is there a method to this madness? I think it might have to do with where the movie was created. Seems like our movies coming from ffmpeg work and Media Encoder does not. Is there a flag in the metadata that QTPlayer is looking for?