Logioc Pro X using to bounce surround but still getting a stereo "bounce" channel?

Hello ... I have a Logic X 5.1 surround project on a movie I'm scoring that works fine ... I've used surround for a long time starting in the late 90's on a PowerMac with TDM . However this time my project started out as a stereo one and I later changed it to surround by simply changing all the stereo pan pots to joystick surround pots.

There's now a 6 channel master output channel hapilly playing back in surround.

I've taken every stereo channel out of the mix and changed everything to

surround ... but the MASTER STEREO BOUNCE won't go away ... and there's

definitely a sync issue.

I'm driving myself nuts because the guide audio track imported from the movie plays back out of sync with the movie .. like when you forget to change the CLICK from stereo out to surround, the click will be out of sync with all your surround tracks ... it's quite significant ... maybe 3 frames?

I can of course change the position of the audio guide in Logic to put it back in sync with the movie ... but that throws all the Timecode reference with the picture out of sync ... and disaster will loom!

My project has a huge track count but maybe the only way to fix this is start again with an empty surround project (with no stereo bounce channel)

Can anyone make sense of this?

Any thoughts much appreciated.

Best Richard