DOMUtils.isTplOrExtToplevelNode only looks for a Parsoid-assigned about id. However, these ids are assigned for ExpandedAttr scenarios as well. While, strictly speaking, that type is also a result of using transclusions for attributes, we should review uses of these helper to make sure there are no unintended consequences because of this nuance. We had one crasher in section offsets patch because of this. It is possible there is some other lurking issue elsewhere. We should perhaps clarify the helper name, functionality, and uses to eliminate this nuance.