FCP 6 round trip to Shake problems

Doing a round trip from FCP6 to Shake 4.1, clips are 10 bit uncompressed, when rendering file out of Shake at 10 bit uncompressed clip is all noise. Negates the whole "round trip" as I have to render it out as an Animation codec to be usable. Any suggestions as to why all I get is noise on my 10 bit uncompressed renders?