The connections between the computer with the Sonos desktop software, the NAS, and the Sonos Connect are all ethernet (hard wired). There is no wireless component to this issue that can explain the cut outs.
Nothing wrong with any other file transfer or non-Sonos audio/video playback issues from the NAS. No problems streaming Pandora. My Sonos system setup has been relatively unchanged for a long time, but this problem developed more recently. My diagnostic report confirmation number is 456826391.