Combined and software brightness adjustments change brightness on startup - there should be an option to turn this behavior off

[waydabber]

Discussed in #1533

^{Originally posted by PuzzledUser February 16, 2023}
I'm probably missing something, but I'd noticed that when I start BetterDisplay my 2014 iMac 27" 5k screen often goes brighter (Mac OS 12.6.3). I'd put up with this for a while, but then got curious, fiddled and discovered that ticking (Settings -> Displays) Combined Brightness causes the brightness to change to a different level.

It does this even if I don't have a dummy display active. It seems to somehow remember a previous brightness, but I've not figured out the rule for what it does. Repeatedly toggling the checkbox doesn't cause further changes. After I adjust the brightness (whilst it's checked or unchecked), I'll sometimes (but not always) get a change next time I tick it.

Is this a bug or a feature I don't understand?
V 1.4.3 Build 13588 Non-Pro version (it was the same behaviour on 1.3.16)

[waydabber]