I do this too. This function is the best of the recent forum-upgrades IMOI sometimes like to play poll roulette. It's like a random thread option. There's nothing funnier than voting on a setup for a lld necro, and being sent to a thread about physical augmentation.
Well, there you go.It happened when our colocation facility went titso and we were left with a corrupt D2 forum table. We've tried to restore it to no avail so we decided to leave alone.
It's intermittent, one minute the link may take you to another poll and the next it won't. It just happened to me trying to vote in the "What format" poll in the Diablo 3 forum, I was able to vote but the poll was showing as in OTF but it was in the Diablo 3 forum itself. Bizarre.
The only way to remedy the problem is to wipe the forum, something akin to the 2003 wipe and I don't want to do that.