IANAL and all the other disclaimer.
I believe in most jurisdictions it’s within a judge’s discretion to dismiss such cases on proof that the law was not knowingly and intentionally broken (such as your example, or when the driver of a vehicle with valid insurance coverage is unable to find the ‘insurance card’ at a traffic stop and brings proof of insurance to court. It cannot harm you to ask for Admin. Review (I assume this is a non-court means of dealing with parking tickets) and show that there was a valid permit associated with the ticketed vehicle.
A phone call to the relevant office asking about proper procedure might be a good idea. Obviously, from the perspective of the ticketing officer, that car was not displaying the proper placard and hence was likely parked illegally in a reserved space.