Tracks to Routes Confusion

Hi folks.

Can someone explain to me why there is a difference between a copied track (someone else's GPS track) and the route that BaseCamp translates it into? I'm getting major discrepancies here.

In the attached image, the green is the track I want to follow. I chose to make a route out of it (apparently that's what I need to do) and it got translated to the pink route. Quite confusing, that pink route.

Am I doing something wrong? Any insight appreciated.

Cheers