Our merchants noticed payments are randomly voided after they have successfully been completed.
Our POS initiates payment transactions via Network Pay Display app, everything went fine, i.e. customers dipped cards, signed... and completed successfully as normal. But once in a while, some of those successful transactions were immediately and automatically voided. It's not that customers voided the transactions, neither the POS requested that; it just happened by itself.
And right after those auto voids, if merchants run another transaction, to take the same amount on those same customer cards, everything went fine again.
What could be the root cause and how can we fix those?