Weird, took GO Transit to the #CNE and tapped on and off to ensure I was charged the correct fare. On the way home the balance on my #Presto card was much lower than expected when tapping off. Checked the transaction history. Despite tapping on and off successfully the system later said, 'nah, maybe you didn't tap off" and added on the maximum distance charge. Bizarre! Filled out the webform asking for a refund of the difference. I do wonder if the station attendant double checking that everyone paid when entering the platform somehow messed up the card logic. Given that the activity log shows a successful tapoff at the Exhibition station I am ruling out user error on my end!