You also need to make sure your’re masking the correct channels from the world position - in the above image its set to red (x), and would need to be changed to green and blue for Y and Z respectively.
In the gif, there’s no blueprints. I just have a sphere with that material on it, positioned roughly about 490 units in +X. As I move the sphere beyond 500 units, the points in the mesh that exist >500 begin to warp. Nothing fancy.