Yesterday I was reading a question on MSO which I upvoted. While I still had that question open in my browser it was migrated to here. I instantly switched to the migrated question which at that time had as much votes as it had on MSO. I noticed however that there was no more indication that I have voted. So out of curiosity I clicked the upvote button again and to my surprise this did result in an upvote wich allowed me to effectively vote twice on one post. Is this intentional?