I realize this isn’t necessarily a bug with the app, but is a minor bug for the forum. Personally, I prefer dark mode for most things. I find it easier for my eyes to read things.
As you will see in the screenshot below, the black text of the AntennaPod name is nearly invisible on the dark grey header.
In the forum settings, you should be able to upload another jpg with white (or something other than black) text that is only used for the dark theme.