Map position indicator arrow flips

I have a Karoo 2. When I'm following a route, the map position indicator arrow always point towards the top, regardless of turns (unit is horizontal). However, when I unlock the screen to zoom around, and then re-lock the screen, the position indicator often flips to point towards the bottom!

The only way to get it to point upwards again is to restart the Karoo 2 unit. Why does the position indicator arrow not always point towards the top? How can I reset this behaviour without restarting the unit?