Payments also being processed twice, adding as credit to client accounts. (Latest PayPal Module)

[Skyla]

WHMCS Version: 8.10.1

Hello,

I am hoping someone can shed some light on this bizarre behaviour. We've been using WHMCS for a decade without ever seeing something like this. It could be a recent update or the new PayPal module,  as those were done around the same time. I don't want to point fingers since I'm not sure what the culprit is.

Fairly simple setup.

Payment Gateway: New PayPal Gateway Module (Credit/Debit Card)

It seems consistent; anytime an invoice processes automatically or someone makes a manual payment. The Invoice payment processes normally but also adds the payment amount as a credit. This means if they pay $20 on the invoice for a domain, The invoice gets payed, the domain is registered/renewed, but then the client also gets an additional $20 credit added to their account. Something seems to be double processing the payment internally even though only 1 charge happened on the card (expected $20), and my PayPal balance is as expected with only the $20.

The problem was noticed on the following invoice, which a customer received and automatically paid from a previous credit that was applied this way. I've since confirmed that this behaviour happens to everyone every time now. We're at a point of constantly having to delete the credit from client accounts after payments, hopefully catching them before they are used or a new invoice is generated.

Info:
The Paypal Payment Gateway settings look normal. Only the Client ID/Secret and the Merchant Payer ID are filled in.

The Transactions on the invoice look a bit odd (2 transactions). This is new since the PayPal module and could be related.

Ex:

This was for a Domain Renewal. The domain has the Payment Method set as "Credit/Debit Card" (New PayPal Module) when I look at the domains page.

Payment Gateway Logs are showing the two transactions as well.

 

Then the credit on the account shows up like this (the same exact amount as the full invoice payment):

 

Can anyone make sense out of this? If you need any other info that may help, just let me know.

[Skyla]

Well, it looks like it mysteriously stopped doing that with no changes. We'll have to keep monitoring just in case. 

 

Good luck to whoever runs into this...