Your track might not be valid. Try viewing your surface tool in mocha... does the blue rectangle follow your track well?
You may need to retrack on a different planar area.
If you are still having issues, you can contact Imagineer Systems support team:
Yes this track seems fine. I made a random mask to track and pasted it. It seem to work, however I made another and adjusted the mask a few times thereafter in mocha and when I pasted in AE it gave me the same problem as before.
The previous mask flickers on and off as though all the data didn't paste.