@hjnicol -- it is sad to say that I too am experiencing audio drop-outs on a brand-new Xi6/XiOne Rogers TV box.
However, as a bypass, if I "rewind" a live program by a few seconds, and then "play", then the drop-out vanishes.
I have also noticed audio drop-outs when playing something that I recorded to the Cloud. The above "bypass" does not work.
I will have to contact Technical Support (1-888-472-2222) for trouble-shooting.