I've been processing a lot of my material from last year, and have come across a strange artifact/flicker that I can't put my finger on. The flicker really shows up on "flat", "whiteish" area of the clouds -- or, least that's where my eyes see it. I'll provide two samples via Vimeo below. I *don't* see this same issue on my full frame 6d with sigma art, often times used on the same scenes. This appears to be relegated to my t7i on a cheaper 10-20 mm efs lens.

Both cases were shot with an f-stop of f/9. Both clips feature a holy grail correction, but the flickering seems to come before the exposure time adjustment.

First clip: https://vimeo.com/532747286/fdcc323834
Second clip: https://vimeo.com/532957035/9c35582fc6

Any assistance for this nagging problem would be greatly appreciated. I want to blame it on the cheaper t7i/lens hardware, but I fear it may be user error ... me!