Use discount coupon loopholes

First of all, this plug-in is really great, but I found a very serious problem. When a customer uses a one-time coupon in an order, the one-time coupon will be used by others before the order is approved. After the order is approved, it will be repeated. Orders using the same coupon will not remove the one-time coupon. It should be set that after the customer has entered the one-time discount coupon, others cannot enter it repeatedly before the order is approved or rejected, otherwise the company will suffer serious losses.