Grades Service Score Endpoint: LTI Ref Implementation Issues

When I tried using the LTI Reference implementation (August 16, 2019 release) to POST to my scores endpoint, I ran into a couple of issues:

• Scores were posted from the ref implementation to the scores endpoint at ../scores.json as opposed to ../scores
• The Grades and Assignments spec indicates: "The scores service endpoint MUST be the line item resource url with the path appended with '/scores'"
• The ref implementation always returned an: Error - Internal Server Error despite receiving a 200/201 response from my server
• The Grades and Assignments spec does not seem to indicate any sort of return requirements from the endpoint
• The swagger specification only shows response codes and does not indicate any specific content-type
• It wasn't until I returned an empty `application/json`content-type that it finally stopped giving me an internal server error

Is the intention that we should return the the same created/updated entity with content-type application/vnd.1EdTech.lis.v1.score+json like what comes in with the request body?

Also the following statement is also in the Score Publish Service section (2.4.1):

Any query or route parameters from the line item url must also be added.

What query parameters would possibly apply to a POST endpoint like this?

Thanks!