name field in webhook create causes a 500

I was trying to create a webhook, cutting/pasting what an existing one looks like, and thus ended up with a "name" field in the json to PUT on the create. I got back a 500.  Once I removed the name field, it worked. 

Makes sense the name field isn't allowed in the json on a create since it's part of the URL, but a 500 is probably not the correct response :)