Turns out that a question with an open bounty cannot be migrated to another stack.
This question is off-topic. But, it does have an up-voted answer, so that would lead me to migrate it to Super User, rather than just closing it.
But, open bounty, so I cannot migrate . . .
I struck my, "(despite the community ignoring it and not close-voting)." commentary because, as Ryan points out, the community cannot close vote.
So this is definitely a bug. It means anyone with enough points to put a 50 point bounty on a Q, can nail it open if we don't on-hold/close it fast enough. (If I recall, there's a required stand-off before a new Q can have a bounty put on it.)