Hi @Bisho68 Ambient Light detection may be causing the issue, check if you have this turned on in Eco settings,check too that you have the latest firmware update. Details will be on Samsung Support https://www.samsung.com/uk/support/ Otherwise ensure that all cables including HDMI are secure. if still an issue try a cold Boot by holding power Button on Remote in for around 5 seconds until the Tv reboots. Alternatively unplug from the mains for around 30 seconds and try again.
if still no resolution do a Picture Test, Support-Self Diagnosis-Picture Test.
I do not work for Samsung or make Samsung Products but provide independent advice and valuable contributions.
My Device- S21 Ultra 5G ( SM-998B/DS ) CSC= BTU , 12GB/256GB
One Ui 5.0,Android 13 .
