DIAGNOSIS This is usually an HDMI-CEC/ARC handshake issue. The TV and soundbar are having a minor communication glitch over the HDMI cable, causing the audio stream to drop and reconnect.
FIX First, try a different, high-speed HDMI cable that's certified for ARC/eARC. A cheap or old cable is often the culprit. Then, power cycle the whole chain: unplug the TV and soundbar from power for 2 minutes, plug the soundbar in first, let it boot, then plug in the TV.
IF THAT DIDN'T WORK Go into the TV's audio settings. Set 'Digital Audio Out' to 'Dolby Digital' instead of 'Auto' or 'PCM'. This sends a more stable, compressed format that sometimes fixes the handshake. Also, in the system settings, try turning off 'Simplink (CEC)' entirely, though this will mean you lose control of the soundbar volume with the TV remote.
HEADS UP If you're passing through audio from a game console or other device plugged into the TV, that adds another layer of complexity. Try plugging that device directly into the soundbar if possible, bypassing the TV's ARC port.