Reset Poll Stats Automatically – doesn’t work

I have a daily, recurring poll that I would like to show users, and then clear the data each night so they can answer again the next day. But setting “Reset Stats Automatically” to Yes, a date in the future, and “Reset Stats Every” 1 Day, does not work. The stats simply don’t ever reset. Is there some other feature I need to activate to make this work? I have tried various reset date/times and hour/day but under no circumstances do the stats automatically reset.