10.13.6 (High Sierra): Invoking Preview when in Sunset Mode causes full daylight mode
Bizarre. Have had Flux 40.1 since 2019. Today (7/26/2020) with flux in "sunset", invoking Preview causes flux (or the OS) to change to full daylight color and brightness.
This effect used to happen with a previous version of Firefox, but doesn't occur any more.
The Preview effect is most annoying.