Probably due to the pc graphic card struggling with the 3D grass courses, although 3D grass ask only for a bit more of pc & graphic card performance. If you amount of pc ram or graphic card are just running just to the limit simply change your graphics within the game a step down......my suggestion :-)
Exactly my issue due to my lower end machine.. right now, I have the graphic settings to where non 3D courses render and run very nicely, I am not about to change that just for 3D grass. Interestingly enough, Spanish Bay plays just fine, but Augusta and Pebble Beach was just a mess to play... meter hopping and skipping all over the place. I am not upset though, as long as there are non-3D grass versions, I am good. At some point I will finally upgrade to a higher end machine, but for the games I am playing at the moment, it is unnecessary... whenever I want to play a game with nice graphics --------------> Xbox1.