iOS software update might actually be the cause of issues with AirPlay. If your iOS Software is updated still facing with the issue then follow the below two steps

Reset your network settings on your iPhone or iPad To go to the reset setings - Settings > General > Reset, and tap on Reset Network Settings. Force restart your device

Yes, you should turn off the f.lux feature that switches it then. (See Color Effects).

I also have the same bug on Mac OS Catalina; it only works when opening the application afresh, but stops working when it has been running for a longer period.

That is interesting - we will check it out. These are optional tags but we preserve them when we modify the system profile.

I noticed that when in Clamshell mode, Flux obeys the enabled preference setting of "Disable for full-screen apps", and so actually disables Flux while the MacBook cover is closed and the external display is in full-screen.

But really, and ideally, i'd rather Flux is disabled when both displays are active (MacBook and External Display, and not in Clamshell mode), and even better, disabled for either (or both) screen depending on which particular screen is in full-screen mode.

It's something to take note of.

How to Get iMessage on PC 2020 Edition : https://imessageapp.net/

I can see this is an old post, but I had the same problem and recently discovered how, I put my wake up for 2am or until the setting said 'bedtime' then you can manually change it on the scale down to 1200k, and it stays!

I'm not able to adjust my screen brightness after installing flux.

@lorna I would respectfully ask this stance be reconsidered. Working at night and trying to sleep with sunlight means a dynamic and chronically corrupted sleep cycle -- and since there is no consistent schedule, having full manual control is the only alternative.

Just another sidenote while still having this problem, that when the mac returns from standby (monitor off etc.) to the login screen, the cursor color adapts to the flux-color, only when I am loggin in by inputting the password, the cursor changes to being 'white'. That may be interesting to anyone.

Thank you.

=====I have found a solution to the screen flickering=====
With chrome or opera, install the extension h264ify. This works for me to end the flickering. Not sure about Firefox. I had to register just for this post because it's so sad to see you guys flounder without a real solution.
Best,