@DTS Engineer
I've submitted a test project to FB20706282 for the first issue.
To workaround, I have to use this way to set the color on popover right now. But I don't think it should do that. It's absoultely a bug.
button.configuration?.background.backgroundColor = UIColor { traitCollection in
traitCollection.userInterfaceStyle == .dark ? .white : .black
}
There is another similar problem on the UISplitViewController. I reported before FB19067917, and it's fixed.
For (FB20928471), it's a similar problem, and I also left a comment on that post https://developer.apple.com/forums/thread/806665
Yes, the popover color will be correct if you dismiss and open it again. But it should be updated immediately after switching dark/light mode.
I don't have any workaround for this. It's also affecting to all Apple's apps. It's a serious problem.
As I remember correctly, this two issue is occoured since iOS 26.0 Beta 3 at the same time.