Cryptopay on a Wash Select II occasional double charge?

[GoBuckeyes]

Has anyone experienced a customer being charged double for a wash occasionally? I've only had two people in the last month or so, or at least that have notified me. They happened on different days and they were different washes. In both cases the customer used the swiper and not the tap-n-pay. They called and said they got charged $20 & $24 and when I look it up there are two $10 and $12 washes for those customers. What could they be doing that somehow causes this or is it a Cryptopay issue? Thanks

 

[Toms PTcarwash]

I have had this happen occasionally on my ACW4 with cryptopay. So far it has always been the customer with zero patience. Looking at the videos, you can see them swipe the card multiple times instead of waiting a few seconds for the card to process. They get a wash, and the person behind them gets a free wash.

 

[DPD36]

I had a similar issue with Cryptopay on a Goldline. It would happen every 500 or so washes. The customer would swipe and the Goldline display would show a 25 cent credit, but in reality it was charging the actual price to the card. After a minute or so it would clear that transaction without triggering a wash. The customer would swipe and select again and get their wash.
I tried for over a year to figure this out. About six months ago I disconnected the coin acceptor and I have not had the problem since. Probably the most aggravating intermittent issue I have had.