My phone is an iPhone SE with iOS 12.3
Every SAB app has the bookname and the chapter number in blue in the menu bar. It used to be in white. I didn’t make any changes in Styles. Even in Simulator it is in white. (I may have to update Simulator/Xcode because at the moment it shows iOS 12.1 in Simulator)
Can you share a project? You can send it in a private message.
@Friedo has been working with @david_moore1 on this issue. We could not reproduce it. @Friedo said that he noticed that the text size was up one notch in the iPhone settings. He change to normal and then back to the original size and the issue went away. So this seems to have been a bug in iOS system software.