I just read your post and i know its nearly a year since..
i had the same problem, and could not find a real solution,
except that when i export in after effects using file->export -> quicktime movie and use the XDCAM codec, they will play fine in final cut… if i use the render queue the exported files will drop frames in FCP !
its pitty not being able to use render queue though, but at least i could finish my project…
i suspect an after effects bug.
o