I had the same problem with the TV receiver, let me guess your soundbar is also mounted on the wall... The problem was that the rear-facing sockets (in this case HDMI) are good for standing on, but when wall-mounted the cables are bent too tightly. You need a 90° plug adapter pointing downwards digitec No. 747022 (and a new HDMI cable) and then you no longer have dropouts. It has been running reliably for months now.
I've been meaning to write that in the review of the soundbar for a while. Otherwise it's top-notch.
Unfortunately, I couldn't find this information anywhere at the manufacturer's or on the web in general. With a bit of luck, someone else will answer your question.