Problems by turning the drone

Hello guys.

I am new in this world. The drone from the company I work for is having problems when turning. Instead of turning directly to another line, the drone flies first to another point in the horizontal, and from this new point, it turns to keep its journey on the other line. Which parameters in Mission Planner do I have to change to modify this? I am really new in this area, and have unfortunately not so many knowledge. Can someone please help me or give a light in wich direction i should go to?
Thank you!