Yes. From Motion, I export to produce a self-contained quicktime and in FCP, import that quicktime and ensure that for that item, anamorphic is ticked and the field dominance is set to none.
Just been looking at another sequence which is uncompressed-10bit and exactly the same issue. Fixed by simply bringing in the Motion project. So it seems unrelated to the codec used in the sequence – very weird.
Tim Burgess