Hi George,
Here’s a link to a screen recording:
https://youtu.be/LjBDUiAy5yc
I start by showing the property I am animating which is a bend deformer rolling out the tongue. Then I set the keyframe positions and show how the first keyframe position changes to the same as the second keyframe once that is added and there is no movement. I then show the F curve where you can see the values are different but have no effect on the deformers position.
I then delete everything and animate the position of a square in the same project to the same effect. Lastly, I hop over to a new project where I have copied the tongue and here the animation of the bend deformers position works fine.
Thanks for taking a look at it. Hopefully all of that makes sense!