Linear Position Drive Cannot be Modified During Runtime

When I try to change Linear Position Drive properties during runtime, they have no effect on my scene.

Details
I have two actors that I am constraining with a Linear Position Drive. One of the actors is set to kinematic while the other is dynamic.

If I use the following constraint settings and hit play, the 2nd actor is pushed away as expected.

20088-settings.jpg

Now, trying to do this in runtime, I set position target to zero and change nothing else.

20089-target0.jpg

I then add the following to my level blueprint.

When I start the game and press F, nothing happens. If I pause the scene and look at my constraint actor, I can see that the Linear Position Target has correctly been updated to -50, 0, 0.

It looks like my rigid body was sleeping. Calling Wake Rigid Body after setting the linear position target fixed things.