AAF-Export does not export Audio Track A1

I reported this issue some time ago and thought, that I solved it. See http://community.avid.com/forums/p/160143/808148.aspx#808148

However, this is not the case. Actually when I use AAF-export with copies of all media to a folder, it only exports Audio Track 2 but not Audio Track 1.

I made a small test as follows:

1. Created a UHD50p project.
2. Linked to three UHD clips, and transcoded them to DNxHR SQ.
3. I created a timeline and placed the three clips on it.
4. I run AAF-Export to a folder with options "copy all media" for video and audio. While the export progresses it says: Exporting File 1 of 9 .....  Exporting File 9 of nine.
5. If I check the export-folder, it only contains six files, with audio track A1 missing for all clips.

I repeated the test in a 1080p50 project, and in a 720p50 project and got the same results, Audio Track A1 is missing.

I hope, that someone can confirm this, or identify a faulty procedure on my side.

Joachim

AAF-Setting