You've probably moved a layer of the button (e.g. the highlight).
In the menu view, turn on the various button states (normal, highlight, select). Which one is the "moved" section.
If that is it, I would delete the button and redo.
I tried that. They are all aligned perfectly.
I also tried different buttons. And I tried making my own button with the work PLAY. It also shifted to a different position. I don't get it.
For that menu, do "edit in photoshop." What is the pixel size of the menu?
Is this the only button?
Where are you seeing the shift? In Encore preview?
I do not see such shifts, but you may find that it does not in a burned disk. Just FYI. I would fix it; such appearances should preview correctly.
figured it out... my menu was the wrong format. It was SD instead of HD.
Encore just doesn not adapt to wrong menu sizes! Glad you got it sorted.