Need help with Intersection Marking Tool

Pretty dumb question, but isn't the green line supposed to be curved, not straightened like that? If yes, then how do I fix it?

https://preview.redd.it/q9f7zjqmnktg1.png?width=1486&format=png&auto=webp&s=acc120530173d1c7b8fe39baf1cd975945eb138d