Get/set vector 3 causing problems

I'm working on a golfing mini game and I've encountered a very strange problem. I'm using an empty game object as a golf ball dummy so that the camera can follow the ball smoothly without rotation and jerkiness. (It's also being used for other things such as player placement and such.) I'm using get/ set position to get the position of the actual ball and set the dummy ball to the same vector 3.

Here's the problem: When I add force to the main ball and get/set is enabled on the dummy ball, force is constantly being applied to the main ball! It should only be applied once when striking the ball, then depend on physics to roll to a stop. Instead, it continually rolls along the z axis. (And even gains speed in doing so!) Just to clarify, "Every Frame" is unchecked.

I have been using playmaker to do my scripts, so an example script is not necessary. If you could explain to me in plain english what could be causing this, it would be greatly appreciated!! Otherwise, please let me know if more information is needed. Thank you!!