Man of Honour
Not an acronym but I read product names a lot but never heard anyone say them. Like Asus is A-Zeus, I thought it was eh-suss...
On a related note, I recently started watching military history videos by a German historian, mainly about German military in WW2. Unsurprisingly, they pronounce the German words correctly. Quite a few are not pronounced at all like I thought they were after reading them in history books.