This question already has an answer here:
Before it was migrated I upvoted the question on Meta Stack Overflow:
..and the vote was carried across to Meta Stack Exchange, but it doesn't think I've voted yet:
..meaning I can upvote the question again:
This bug could exist because the system may only migrate the number of votes, not including who actually voted.
If so, it can't really be called 'Migration, but rather be called copy and delete.
Is this bug intentional?