After using SQUARE for years through Gravity forms recently I started seeing an issue. Users on my site see the error below and then try again and the order goes through twice. This is new and I have not changed anything that I am aware of.
Credit Card Payment: Card nonce already used with a different idempotency key;
I am having the same problem. Forms throw error: Card nonce already used; please request new nonce. However, the charge still goes through. But the customer doesn’t think so based on the error message.