A small line artifact appears above the lowercase letters 'o' and 'w' near the base of the screen. This will appear on 'minecraft' font that is printed (not, for example, on a button). Any effects on the text, such as shadows or coloration, also apply to the artifact.
Tested with text in the hotbar, the chat section, the world list, and the settings. Screen resolution is 1920x1080; possibly only affects the iPhone 6 plus.