Not really a "glitch" so much as an oversight, I guess.
When making a new poll with advanced settings (ie. allowing users to change their vote), if you hit preview before you post the thread (which I always like to do to in order to proofread my threads), all of your settings are reset to their defaults, forcing you to either change them a second time, which is annoying, or not even notice it, causing you to post the poll in an unfinished state accidentally.
You can't change poll settings after the poll has been posted, either, so you either have to make a whole new thread (which is awkward and unnecessary), or just kinda deal with it.
So yeah--could you make it so when you hit "preview", it saves all of your chosen poll settings? That would be great.