Below is a repost from "kungphu" it was never responded to by Reallusion. I would like to know the fix to this situation for a recent project.

Unreal Livelink Animation Sync
I've tried this with various frame rates for unreal Project (i.e 30fps or 60fpd) and also viewed my own transfer frame rates to ensure they're at 50PFS or higher. All settings in Unreal are correct for either a 30fps project or 60fps project. Whatever animation I have in iclone always seem to be longer the same animation recorded in the Unreal sequencer. For example if I record audio with Unreal, the audio file plays through at the normal speed but the animation will be completely finished and the audio will still be going. It is not in sync with the audio or the iclone timing at all. The sequencer file will have the same number of frames but the animation will be sped up.

For non speaking scenes this is fine, the rendered video will just need to be time stretched in an editor. However, if it is a speaking scene it is an absolute nightmare to deal with. You have to guess on how much to time stretch the rendered video and then you have to nudge the video file over. The results are hit and miss. If you time stretch incorrectly, you will never have a satisfactory lip sync. I mentioned this in the forum and another LIvelink User Bassline303 mentioned that he had the same issue and we'd have to wait for a Livelink Update.