Look like a bug, which has been reported. Here's what you can do to overcome it...
Using the animation graph, plot the zoom IN.
Create a Sequence 2. Go to the Sequence tab (top-left) and drop sequence one into Sequence 2. Now reverse it in Sequence 2.
You might also plot the zoom IN and OUT as a single effect in Sequence one. Zoom in, hold at that level if desired, then zoom out.
That would look something like this...
