fx.shadow.js assumes that the next element is always the shadow element and modifies all of its child elements whenever the dom changes. The shadow is not always the next element, and in fact is never the case after the shadow is removed.

So after a shadow is removed this causes the fx.shadow code to change the size of any element that is in the position where the shadow used to be.

The fix is simple, and only requires changing line 69:

$element.next()

--should become-->

$element.next(".fx-shadow")