I'm thinking he tried to upvote his comment:
https://steemit.com/contest/@shadowbot/up-vote-contest-winner-gets-5-sbd-contest#@kayyam09/re-shadowbot-up-vote-contest-winner-gets-5-sbd-contest-20180224t092931288z
But he send instead 0.5 SBD to @promobot for https://steemit.com/contest/@shadowbot/up-vote-contest-winner-gets-5-sbd-contest
And he did the same mistake with @mitsuko, another 0.1 SBD. He also tried @inciter with the right URL, but it seems that they are not upvoting comments.
Due to the structur of the contest, it's more a SteemPower (Self-upvote) and Bot-knowledge (Bots that will upvote comments for payments) contest. 😂