TV has started getting an intermittent white flash, only for a second, only does it when using Fire TV or Freesat, was resolved previously by a software update but back again!
Have the same issue with my QN55Q7FAMFXZA (2017 model) See with any HDMI device which for me is TiVo and PS3. Had 2 techs out and said tv was fine because they did not see the flashes when they were here. Would never buy another Samsung TV again!!! Obviously a software issue with all 4k 2017 models.
Mine has been doing it since new, went away for around 6 months. Apparently it's a software caused issue, but obviously with various updates going on, the glitch came back.