I took my shiny new Z8 for its first outing on Friday and it's certainly a step up from my D850. I was however surprised at the occasional radical difference in exposure of images within a 20 fps burst. The two images below were taken within a second (2 frames separate the images) and the light did not visibly change - it was a grey, overcast day with no sun. Shooting RAW, Auto-ISO at 1/3200th, f6.3 at 400mm on a Z 180-600, the first (bright image) is ISO 3200 and the second darker image is ISO 560. It has happened in other bursts as well which is odd as they are a fraction of a second apart - any ideas or is this a known thing?
I accept that my shutter speed was too high for the situation but that surely wouldn't explain why 1 shot in the sequence should be so bright and high ISO would it? Am I missing something obvious?