For what it’s worth I have only encountered something similar to this issue you’re describing where there is a video clip in FCPX with the audio expanded, and I shortened the audio to a fraction of the length of the video clip…. but in LPX, it plays the entire length of the audio clip – to match up to the length of the video clip.
Easy to catch and shorten/edit in LPX, compared to what you’re describing which is more complex to solve.
Im just in the testing phase of using FCPX and LPX for a feature project, so I’m sure there will be more issues to come.
BTW, I’m trying to resolve why my audio levels in FCPX for my dialogue clips read much, much, lower on the meter than after migrating that clip into LPX using the FCPXML protocol. (using the same multimeter in both programs) Please let me know if you have any similar experiences with that.
FCP X 10.1.1
Logic Pro X 10.0.6
Mavericks OS 10.9.2
iMac 2.9 GHz Intel Core i5
8gb RAM