Audio drops with Roku Ultra 4640RW with Toslink optical
For about a couple of months I've noticed audio dropping intermittently on my Roku Ultra 4640RW. It's connected via Toslink optical to an old Bose Lifestyle 28 Series II and via HDMI to a Panasonic TH-50PX50U plasma TV. I noticed that when the audio drops the Bose shows that the signal changes from "Dolby Digital 2.0" to "Dolby Digital 2.1". Rebooting the Roku helps for a while but the issue comes back later. It happens when watching Netflix, YouTube TV and OnDemandKorea apps. Any ideas?