try recalibrating it, if it doesn't work maybe you have to repair it

did tht many times, via godmode 9 and settings

to be honest its just that tiny portion that really doesnt affect any games, you never need the outermostborder, cant even use it here.

get it repair

i had this problem with my old 3ds, the left side of the screen extends the cursor further to the left. cant fix it urself