Editing text that's just inside a <small> works well. However, when that <small> is inside a table cell, you can add additional text to the end, but can't edit or cursor through its existing contents. Testcase here. Ideally, you'd able to, but since this situation doesn't arise very much (although see, for example, the Chapter-wide financial trends report 2013), just showing a visual indication that the element is alienated would be pretty good.