That's exactly what it has to do with. The only fix is for me to go into the database and manually delete the duplicates. That is quite a challenge and I prefer not to do that unless it is really causing problems.
Not causing any problems really, the results are still accurate, just shown more than once. I take it new polls won't be effected by this? If that's the case, I wouldn't worry about it, I just wasn't sure if it was something that was effecting new polls as well as old.