I would assume they meant "oneway" directional arrow. But that way which seems to be indicated https://www.openstreetmap.org/way/171708651 is already pointing towards the tunnel Trsat on SW, so there is nothing to update/fix AFAICT. Perhaps user had GPS error or was using some old maps? Or wanted to indicate some other road? 

Unfortunately, as the Note was submitted anonymously, we have no way to check with the user to find out what problem they faced. So without additional information, there is likely nothing to fix. #notenoughinfo 