We've received several duplicate submissions (payments) on two of our forms and I cannot determine if the cause could be the user clicking Submit twice? Or some other type of error? The two forms that we've caught so far have come from https://www.santafebotanicalgarden.org/support/membership/ and a workshop that is no longer up. There are other submissions that have functioned correctly so I'm uncertain if the form can actually charge twice by clicking twice on Submit?