It should have been always set (at least with a certain muxer). But different muxers handle it differently.
I have no date set when it will be available for you to test yet.
It's not what I was observing. In fact, I rendered the same video multiple times until I got a version without the timecode track. A bit of a pain 😅, but until that new version is out, it's what I have to do, otherwise the files won't direct play for me with Plex.
Hopefully you can get that new version out soon 🤞. Keep up the good work.