I’ve come across a bug when changing color schemes in apps. It appears that if you have a verse selected (i.e. for annotation), then change the color scheme, it doesn’t always change the background color. So selecting a verse, then changing to dark color scheme usually gives me something like this:
Sometimes if you swipe to another chapter and come back it fixes it, but maybe only if you swipe a few chapters away (like the image is in some sort of cache)? It also seems to have this problem when you have opened up a footnote, tap to close the footnote, and immediately change the color scheme.