It is about  question on unix SE migrated from the SF.  What I did:   I voted the question up (on SF). Voted to migrate it to unix SE. It was migrated (my vote was the last needed). Followed the migrated question on the unix SE. Its vote count was also migrated from SF. But the up arrow didn't signed that I already voted this question. Thus, I was able to vote it up again.   Currently the question has 2 upvotes from me, but from different sites.  I think, maybe the question owners are perfectly synchronized on question migrations, but its voters aren't.  It is a bug or feature?
was created on Server Fault, answered on Server Fault, I upvoted some of those answers on Server Fault, and then moved by consensus to Super User.  Now that the question is on Super User, I can upvote the same answers I previously upvoted on Server Fault.
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