You already have voted.

Hey, one player reported me, that he typed /night (alias in server for /lvt no) and the server answered "You already have voted". He said this isn't possible. I had not this problem and I don't care about it. I just looked up my server.log and found an error at this date, where it was reported. It's not a such big bug, but... here is it (and sry for bad english): http://pastebin.com/wzvHccSV
I use 1.9.