I' ve seen a few posts about audio not syncing after a few minutes on Frame and Smart TVs. The moderator's response is usually to make sure the device is up to date and if not, a factory reset is advised. However, in my situation this only happens with Samsung TV Plus Live news channels (movies do not seem to have this issue) and it's happening across multiple devices (Smart TV's, S21 Ultra, a new Samsung Book3 and M8 Smart Monitor).
If I switch channels momentarily and return the sound is in sync for a while (~5 min) then it starts to fail again which is also reported in other posts. But it cannot be related to specific devices, code updates or performing a factory reset, there must be something else causing the audio and the video to fail on broadcast programs in TV Plus.
I am sorry to hear the Samsung TV Plus Live is having audio-video sync issues, and can understand how annoying that is. If it only does it on that specific feature, I would recommend contacting the app developers. You can do so by emailing them at m.tvplus.sec@samsung.com. I apologize for the inconvenience.
