tl;dr: Bluesky replaces its "Follow" button with a logo watermark in iOS screenshots by exploiting `UITextField`'s `isSecureTextEntry` property—rendering the button inside a secure text field's layer, which iOS blanks out during screenshots, revealing the logo beneath. The same trick is used by Signal and Telegram for private content, so Apple is unlikely to patch it. Community reception in the PR thread was largely negative before it was locked.