Done with gooseberry branch on linux (not able to test with 2.74 since there is no "Use sequence" scene support in it)

to reproduce follow those steps :

1-in default scene, go to VSE and enqble AV-sync
2-import a video file with sound. adjust it to start at frame 1 of the timeline.
3-adjust start and end point of the timeline to fit duration of this strip
4-create a new scene (lets call it -edit scene-), go to VSE and add default scene into it at first frame (play the edit, everything should be fine and sync)
5-go back into default scene and change start point to frame 125 for exemple
6-go back to edit scene and playback your timeline.

2 unwanted things happens :
1 - strip audio is off sync, even when pressing refresh sequencer.
2 - in the edit scene, the default scene strip has changed in and out points. should display 25 black frames, then play normally starting from frame 25. Default strip scene in edit scene should keep sync as it were. frame 125 in default scene should still be frame 125 displayed at frame 125 in edit scene.

Workaround : go to the properties of the default scene strip in the edit scene. Set to 0 (which it is by default) the trim duration (hard and soft) for in and out points : strip adjusts its duration as it should (at the end of the strip). Then move the strip to make it start at frame 125 : that's how it should be. And sound is in sync again !
So apparently its not updating well when you switch scenes duration when the are added into one other as sequences...