Sometimes I find that the Maliit keyboard extends beyond the edges of the screen. I'm not sure what triggers this. It might be simply from waking my Surface Go 2 up from sleep. Or, it's because I wake it up in portrait mode. It doesn't always happen. It is broken about half of the time.
To make it fit the screen again, I go into Settings>Virtual Keyboard (KDE Neon), select None, Apply, select Maliit, Apply. Then the virtual keyboard fits the screen.