SOAP Call To Flow Service, Store Procedure Failure Causes 403 Forbidden Return

We have a SOAP client making a call to a flow service through the standard SOAP Processor. When an error occurs, such as an addInts service with 1 + ‘A’ (just trying to force an error), we get back a valid SOAP fault from the catch block returning the data via the EXIT function.

When this same service fails at the stored procedure step, going through the same catch block and pulling the same field form the lastError document, we get a 403 Forbidden error back to the SOAP client.

Has anyone seen this type of behavior? We are on IS 7.1.1 with a bunch of hot fixes. I do have an SR open but trying to get a fix or workaround sooner rather than later.