In settings search and open Samsung keyboard, tap keyboard default settings - clear cache if not solved reset to keyboard default settings and restart the device. If it helps, in my reply 3dots accept solution.
It's a bug in One UI 6.0 update in keyboard, when it's appear immediately click on close app or send feedback. Also wait for next update may be fix it by Samsung team soon. If you like please accept as a solution it's help to others users also,click on 3dots in my reply section and click on accept solution. Thanks.
