On Android, there's a spellchecker popup that occasionally appears over the keyboard, getting very annoyingly in the way. See for example this unanswered question with screenshots.
It looks like a feature of the keyboard, but it's not, and so I looked and I looked and I could not find how to turn it off.
The answer is to look for how to disable the spellchecker in the keyboard section of the android system settings, not in the android keyboard app settings.
See for example this answer on stackexchange.