@adent42 I think there might be an error somewhere in the Interpolate Behavior. In the project I have attached the screen is overlaid with an actor, after 2 seconds this actor reduces in size and its position should stay locked at the bottom of the screen. But you'll see once the actor begins to resize it jumps up a few pixels and then reduces in size as expected.
The Interpolate Behavior is set to transition over 1 second. If you reduce this time, the amount of pixels the actor jumps is increased and if you increase this time the pixels the actor jumps is decreased. I'm thinking there might be an error in its calculations somewhere?