Yes the voice-acting seem hollow and out sync. Hopefully this will be fixed because poor audio is worse than poor animation to me, indeed, it was the first aspect of making movies I learned was crusial part in any production as it has the power to enhance or entirely ruin the viewers experience. So hopefully this is just a streaming issue with the trailer.
I rather like Terence Stamp's part in this, good voice actor... Usually, and the unmistaken voice of Sean Pertwee(probably most recognisable as the role of "the father" in Equilibrium).
Animation looks pretty good though, I have to say so hopefully this audio problem is only related to the trailer and/or streaming issues.