Being a new forum member, I think this information can be helpful to other members viz:
I have recently watched 3 seasons of 'The Good Doctor' via a Now TV Smart Stick on my Sony Smart TV / Virgin Media's 200Mb Wifi BB.
However on several occasions the audio would become distorted and/or go off half way through an episode, usually when viewing after 11pm.
I solved the problem by transfering my viewing to a Samsung Galaxy A6 Tablet's Now TV App and 'CASTING' to the TV ........Audio perfect!
This action may also work with other program audio problems. Good luck.