This Volokh post takes on the Virginia Court of Appeals' decision in the Miller-Jenkins case.
One of the commenters gets to the nub of the matter, as I see it:
"I am curious as well whether under Vermont law the child custody determination is considered an intrinsic claim/remedy in the dissolution of the civil union as it is in divorce actions. This would create the Catch 22 where a parent wishing to dissolve a civil union (so as to sever the property/inheritance/etc. rights created thereby)might have to submit to Vermont's jurisdiction over custody issues because their new home state doesn't recognize civil unions or a cause of action to dissolve them."
The related discussion poses the question, could a Virginia court dissolve a Vermont "civil union"?