Not sure if anyone else is seeing this, but I can't choose to add a soundtrack audio clip that starts at some point other than the start of the video. It looks like it is visually in the editor, but when I go to play it, it jumps to the front. I also can't delete audio soundtrack from project once it has been added.
Update: Odd, exported video didn't have soundtrack, then I went back to editor and they did show there, even though pre-export I could both see them in timeline and hear them in preview. When I re-did this not zoomed in on the timeline I was able to delete them.
As a note, when I do add soundtracks (built in ones) they sound just fine in preview, but are crackley in export. Not sure what cause is, but until resolve that the soundtracks are not useful.