This started a couple of weeks ago - watching live TV (terrestrial freeview, any channel) or playback via wifi, picture freezes for a second, then rushes to catch up. Happens again a few seconds later. Sound is unaffected.

It was intermittent - problem one evening, no problem the following evening - without any changes being made to the box. Now it is constant.

I have since upgraded VIX to latest version, but it has made no difference.

Any suggestions?

Box was bought in January 2020.