Same problem here! Logic will randomly choose which tracks to export. Sometimes if I choose to export a track, it will go through the motions and then not save the track to the destination, then if I do it again, it will actually work, but assign a _1 to the filename as if the first export already exists. This too, is random.
It appears this is definitely related to checking "include volume/pan automation" - if it is unchecked, it will export with no problem. If it is checked, the export is a crap shoot...
in addition, it will randomly convert a track from mono to stereo! Any track I export that is already stereo, stays stereo, but tracks that are mono are getting randomly exported as either mono or stereo.
Seems like a severe bug here as one cannot bring a mix from one studio to another to continue a project in something like ProTools... HELP!