Api Definition/OpenAPI - Api Management Import Failure

I have an API Management Service and an Azure Function. When trying to import the OpenApi spec via the API Management service 'Import Function' button I get an error. The error states something similar to 'values in your route template must be included as parameters to the function'. So if i create an httpfunction and use modelbinding by following [HttpTrigger]MyModel model it is bound with both values from the route and the querystring if its a get request. So the question is why do I get this error? Is it that the open api spec is being created incorrectly or?