I checked out your scene.
The issue was that your Out Scene director hadn't been updated for the flipped version. There was a "D" marker on frame 0 of the Out SD. This "default frame" marker essentially indicates to XPression that when the scene is being put on air, that scene director should be "cued" up to the position of the "D" (default frame marker). In your case that is not really needed on the Out Scene Director so you could just rightclick on the timeline portion of the Out SD and click "Clear Default Frame Marker".
You will have noticed that when you scrub the Out SD that the graphic jumps to the position you were seeing it in (way on the left side of the frame), so you would need to fix all the keyframes in this scene director.
Generally the only location you really need to play a "default frame marker" would be at the end of the IN scene director. The reason you would place it there would be so that you can leave the IN scene director scrubbed anywhere you want in layout, and when playing the scene in a back to back situation where only the Update IN scene director would be played, the objects in the scene get positioned as if the scene were fully IN. Without it, when going back to back you could end up with objects in the wrong location..
There were a few versions of XPression that erroneously created the Default Frame Marker at Position 0 of every scene director that got created.. (this was fixed in 5.95 build 3259).
#XPression