Does you Samsiung have local dimming?
Your image appears to only contain only the backlighting which can vary when no actual video is being displayed.
Do you see the problem when displaying video?
Have you tried lowering the backlighting percentage?
I thought so since the stripes look they are caoused by incorrect loca dimming valuies for every other zone.
Do you have any way to adjust or disable the local dimming? If so what effect does reducing it or disabling it have?