Customer able to add their own custom discounts?

[Grockell]

PrestaShop v1.7.8.6

PrestaShop Checkout v2.20.2

Our shop has a new customer (registered 9/25/2022) They've placed 7 orders since.  The first three look fine, all PayPal Pay Later through the Checkout Module.  The next 4 all have massive discounts that I cannot track the source of.  The last 2 discounts were exactly the cost of the order (which might be the only reason this was caught, the first two even when most the order was discounted didn't "look" weird when the order was being processed).  Customer is not answering emails or calls so we have no idea how these were being added.  Has anyone else seen anything like this?