We don't know of a problem here but will look into it. To help us could you say:
1) What sample rate you are running.
2) What numbered routing are you using (routing 8 firewire could mean many several).
Also, since the problem may be at your end, could you try changing the routing about to try and determine exactly where the signal is getting lost – for example, exchange channels 5/6 with 7/8 and see if it swaps or remains the same.