I'm sorry, I missed your previous comment. I captured HTC 10 screen only with Iphone 8+ camera, but it seems to miss any flicker, probably due to some kind of algorithm in iOS to make videos more fluid, I couldn't make it reveal the same things I observed while using HTC 10 to capture these videos. I'll probably buy another HTC 10 in coming months once battery in mine dies (it's at 60% capacity at the moment), so it might be interesting to capture both devices one with another.
Regarding microscope - it's an old soviet semi-toy microscope called "Naturalist" - exactly this one: https://www.ebay.ie/itm/Microscope-NATURALIST-Vintage-PLASTIC-CHILDREN-TOY-USSR-Box-and-Accessories/123554698744?hash=item1cc46f15f8:g:9x0AAOSwMNxXanjk:rk:12:pf:0
Unlike most current toy microscope this actually works and allows me to get decent zoom-in to see individual pixels.
I think blue light will be on every recording since it's present in gray tones and camera capture can be a little bit different from the source due to encoding / compression. I think some minor flickers on my videos are probably compression artifacts, but there is definitely an obvious alternating flicker pattern clearly visible too.