Sorry, trouble getting these screenshots to work right.
Screenshot above shows result after using this code:
I also tried with the cameras world position, and both using the AddOffset and SetLocation nodes. They all give the same result.
The actors 0,0,0 location is right beneath the camera. There should be no movement on the Z axis, only sliding along the X and Y plane.
I tried isolating the vector multiplications to only be on X and Y but it is still always moving up on the Z axis.