CFC as web service gotcha

I found a quirk with a CFC setup with access="remote" today and wanted to blog for future reference. I have a CFC that takes 2 parameters, 1 is required, and the other is optional. When I invoke the WSDL, and only pass along the 1 required parameter, I get the following Error Message: Web service operation "FunctionName" with parameters {PER_ID={100623},} could not be found. Since I recently added this second optional parameter, I tried refreshing the web service stub to no avail. To get around this, I had to pass in the optional parameter with its default value to make sure that logic didn't run any differently.