Generally schools that have their own examing authority have what is called an Airmen Certification Representative(ACR). So while any of the chief pilots can give your checkride, only the ACR can sign your certificate. Due to physical location differences, the ACR for a multi campus school may not be located at the same place that you take your checkride, so after your ride, they do the paperwork, the ACR signs it and it is sent to you.
There is nothing shady about this, this is how many schools are setup, but it can provide an inconvenience for the student, as you can be without a certificate for a few days time. If it is a big issue.. you have to be able to fly the next day or something like that, talk to the school.. usually they can arrange for the ACR to be on site when you take your ride, or have a day or less turnaround to get your temp..