export multitrack Quicktime file to play all audio tracks at same time in VLC

Do I need to do something before exporting a multitrack Quicktime file (for broadcast Apple Pro Res 422 HQ) to get my 8 audio tracks to play at the same time in VLC?  When I open it in VLC the 8 audio tracks are there, but it plays only one at a time, defaulting to the first one (Left stereo).  The distribution company says my project is 'left only audio' so it was sent back to me. Thank you in advance for any suggestions, as this is my first time making a broadcast Quicktime file.

How are your channels and roles set up? The tracks that export of course are determined by roles. But the levels and panning are determined in the audio configuration (Inspector). Unless they want a stereo pair, or any panning, configure them all to be mono and panned center.  As in the screen shot I attached, if Pan Mode is set to none, mono channels are all centered properly, without need for any further action on your part.