UMLR — Concerning Transition and its owned elements

is there a reason why a transition's effect and triggers of a state machine transition (section 15.3.14 in UML 2.4, respectively section 14.5, subsection Transition in UML 2.5 initial submission) do not belong to the transition's namespace as members? Both simply subset ownedElement. In contrast, a transition's guard subsets Namespace:ownedRule, which made me think the former ones ought to subset Namespace:onwedMember in lieu of Element:ownedElement as well.

I roughly flicked through the open issues of UML, but did not find anything related to this question. So, if there was not decided deliberately, I would open an issue for that