@MBeat33 noticed some Gravy PayPal failures returning "Failed invalid request parameters" responses and posted a message on slack here. After scanning the logs, I found 37 related failed recurring charges.
You can see them by running the following on frlog1002 logdog -d 202502 INVALID_PARAMETER_SYNTAX
Gravy says they can recharge them on their side, so let's follow that up and confirm they were charged and recorded on our side.