I have an Aura Freeview box and it suffers from lip sync issues. I do not have an audio system connected and use the tv speakers. It does not occur on the tv using the straight aerial connection. Strangely the problem goes away if I change to viewing direct from the tv (I.e. not via the Humax) and the go back to the Humax (live or recording) but the problem reappears sometimes in minutes. I know there is a lip sync control, but this seems ineffective and I don’t feel I should need to be adjusting this on a regular basis.
Using the optical audio connnector directly from the Aura to my Sony sound bar fixed lipsync problems for us.
Going via eARC through the TV (a 2015 Samsung) was the real problem.
Some programs are still not lipsynced correctly but thats a problem with the program – just occaisionaly one is out on SD or HD but ok the other way round.