A:Answer I have seen this before and in my experience it is usually a download speed problem coupled with buffering of the signal. If it has anytime when it does not happen the buffer is full or throughput is fast enough to maintain the sync. If you pause and play and it corrects the sync, then the buffer caught up.
Not easy to say why it happens in every case. No telling if it's a slow source, a slow ISP on your end or too much traffic at some point on the way. It could be too much traffic coming into your home. If you are on a DSL it could be there is too much traffic in your general area for the DSL equipment to keep up with at that time. It may not happen all the time because others are not active in your area.
Most likely the problem is not originating in your TV, especially if a pause and play solves it for some time.
Hope this helps.
