VVPAT has a customised programme written to recognise votes. Experts say that this programme can be bugged. Since the VVPAT is fed with information such as names of candidates, party names and symbols in its programme, it is possible to tinker with the code by providing additional details
The same VVPAT machines printed another extra slip with the lotus symbol during the second round of mock poll and it was rectified only during the third round.