So, I've had this happen a few times, and it seems to be random.
Basically I send a clip from FCP to Motion to stabilize, and it stabilizes beautifully, and I have the boarders set to "zoom."
I save it, and return to FCP, and the clip is there, and stabilized, but not zoomed. So I see the black edges dancing around. As I said, I doesn't always happen, and more often then not, it actually IS zoomed at first, and then after I close FCP, and open the project later, it's suddenly no longer zoomed.
Usually I can reopen the file in Motion (where it is still zoomed) and then just keep re-saving it and checking back in FCP until it shows up zoomed again.
This is really driving me nuts, especially as stabilizing is probably what I use Motion for most, and I love the ability to just go between to two programs like this. However this glitch is a major hitch in my work-flow, so I'd love to know how to fix it/a workaround so as to not continue to have to waste time fiddling with it.