Emojies and preedit text underlining bug

This bug can be detected by  creating simple qt quick project, with only main window and text area inside it. After inserting into the text area  any kind of emojie ( it doesn't depend from which source), then after moving cursor somewhere else (or unfocusing the input field) the emojie will be recognized as a preedit text and it will be underscored for a moment (on some devices the emojies are fully redrawn, what makes this bug more detectable). This is definitely a bug, because emojies are not supposed to be composed at all by the the input method. One line Text input component doesn't contain this bug.