I noticed that too (very annoying right now, I'm trying to write a spec file...)

Sometimes it displays text overlaid on other parts of the line you're on so you think the cursor is somewhere it isn't... do you think that could be a problem with the package, or something hardware specific? Nano is fine on all of my other devices...

I'm thinking it may be something to do with curses (which I think is a toolkit for displaying text on the screen?) - I've noticed that if I ssh to one of my servers and use certain programs like transmission-cli or yast, some parts of the screen don't update properly on the Jolla.