Title display does not handle acronyms correctly

Thank you for reporting this. The app has a title cleanup feature that automatically formats file-derived titles (e.g. turning "my_book_title.epub" into "My Book Title"). This was incorrectly also applied to titles you set manually through metadata editing, which caused acronyms like "AF" to become "Af". This has been fixed -- custom titles you enter are now displayed exactly as you type them. The fix will be in the next update.