Weird video display

[prpr]

Just switched on to be confronted by this:

Menu/Media/Guide made no difference to the video but displayed the correct thing on the front-panel display. Changing channels cured it. Never seen anything like it before...

 

[Ezra Pound]

Was the 'UNCH' part of the normal picture or was it part of the white square overlay?

 

[Black Hole]

I used to have some HDMI weirdies in the very early days, before the first ever firmware update.

 

[prpr]

The item was about a pub sign featuring a Suffolk Punch. The video corruption was not an overlay - it looked like it was double amplitude or similar.
I tried turning the TV off/on again and selecting another HDMI input, but the fault was definitely output related on the Humax.

 

[Trev]

I saw the show 'live' and it didn't do that.