In my App the profile field „Meine Geschichte“ (basically my backstory) can be updated either via the LFD „Das Twitterrudel“ and using the Edit function, or via the menu „update profile“.
When going via the LFD, this single field is not editable at all. On mobile, the keyboard is not displayed, also not after clicking in the field itself. All other fields work.
When going via the menu, the field can be updated on all devices. Very strange.