In a real lotto, every play has the same odds of winning. In this lotto, having a fixed pool of tickets that gets depleted means that every time a ticket is purchased without a winner, the odds of winning improve. Several people have done the calculations and have used that to game the system: talk everyone else into buying tickets, improving the odds until they're ready to swoop in and collect the pot.
If you can redraw the same tickets now, then that means this lotto works just like an actual lotto, so I'd say it's more likely that this is a feature, not a bug.
