I have the same problem, worse on HD channels but lip sync is out on many channels, Fresh flash done on build 705 without restoring a backup and with restoring a backup, same issues, really do hope Technomate read all these posts as I am starting to lose faith in these boxes, been nothing but problem after problem. Channels in particular is STV HD (manuallly scanned in) and several channels in documentary bouquets Discovery, History etc. Tried it with timeshift on timeshift off, reset enigma, reset box

You name it I've done it