To add to your notes, I upgraded to a new PC, also with an AMD 5700 XT and have the exact same issue.
I had to downgrade my Amd Radeon Adrenalin 2020 to 19.9.2 because the newer driver caused several issues I'm unable to deal with atm but at the exact time this visual error came up.
So for me it's either this bug, or buggy GPU drivers... If anyone has this issue I suggest updating your graphics drivers.
iiyama Red Eagle, 1440p 144hz via Displayport & MSI Evoke 5700 XT OC. Win 10 pro.

Have the same problem with a 1070 Ti, after an update brightness control works, and after an other it doesn't...
Annoying

Usually the brightness keys should control the backlight and not interfere, but it sounds like they are doing something else.

You can try right-clicking on the desktop and choose "Intel Graphics Settings". Look in Power and see if any of the settings there make a difference. (Personally I always turn off dpst because I don't like how it looks).

There is also a slightly newer driver for the Intel 620, not sure if that would help or not:
https://downloadcenter.intel.com/product/96551/Intel-HD-Graphics-620

Sure, you can do either of these things:

turn on Options > Use wider slider ranges use alt-shift-pgdn/pgup

Did you set your wake time?

download .icc file, open color management, set as default, check "use windows calibration" in advanced settings.

also realized that v4 never applied my color profile (im using saturation in games for better colors and i can use 50% lower settings now that my color profile doesnt get reset anymore. so on win 7 v4 used to reset profile too i guess)

using v3 atm and it works. safe mode for no polling.
also whenever i launch a game flux stays active, but after i alt tab once the game blocks flux. so i can choose if i want it active in game or not. (prolly has smth to do with win 10s fullscreen. i disabled fullscreen optimizations but in win 7 every game always blocked flux while in full screen)

Does Task Manager > startup have a lot of things missing or turned off?

If anything Microsoft-related, it's probably in the "defender" or "security" logs.

@Delaney said in Today I can no longer control the brightness with control/alt+mouse scroll wheel:

@TwoCables Oh, okay version 4 for windows. Thanks. And that's interesting. I wonder why I could and now I can't. I had to click on the desktop screen to do so but I still found it easier. I'm going to miss it. Oh, and the other weird thing was I couldn't adjust my screen size on a browser with alt/scroll this morning (which I normally can) until I uninstalled f.lux. Then it worked again. This all happened right after I saw the pop up for the f.lux update but hadn't even done anything yet. Thank you though.

You have some sort of program installed that lets you do that. This isn't a feature of f.lux.

Same problem. Gets removed from task manager startup list.

Have you tried putting the flux shortcut on the "startup" folder manually?

Our installer sets things up to run with /noshow to prevent this. Do you have any software that may have removed the flag?

Reinstalling may help if so.

If you're using a Win7 server, you must have Aero activated.

Can you post f.lux options > driver info? Will let us see the versions and other things.

Also please post what it says at https://justgetflux.com/timesync.html