Please can anyone help I have a sony "kd75xh9005bu which i have had about 3 weeks when connected to skyQ uhd I get a flash across the screen about every 3 minutes I have the hdmis all set to enhance I have changed the hdmi cable and sky fitted anther new sky box today but still the same and it’s also the same which ever hdmi socket I use also tonight it has started doing the same on my 4K Fire stick any ideas

(Ps still the same after update to hdmi 2.1 and the same on all 4 sockets)
many thanks