Recurring charges on banking statements are simply to insure that Stripe can store the card for future purchases.
As part of our service, we make the payment process easier by storing the card used for payment so that if you'd like to donate or pay again you can simply select the previously used credit card to do so.
In order to store that card and be able to utilize it again our payment processor, Stripe, needs to tell the bank that the card was saved for future transactions by marking it as Recurring. This does not mean that you have signed up for recurring payment or billing plan.
For more information about this, please view Stripe's documentation on this: https://support.stripe.com/questions/non-recurring-charges-show-as-recurring-on-customer-bank-statements