What version are you running? 2.0.12 What's the URL of the page containing the problem? Using RBClient to update a diff_comment. What steps will reproduce the problem? 1. Create a review request. 2. Create a review and open an issue. 3. Using RBClient, get the diff_comment resource and call update() with no parameters. What is the expected output? What do you see instead? I would either expect the ItemResource to be returned with no changes, or an informative error that indicates that a parameter is required. A permission denied error is strange, since I'm not really trying to update anything. What operating system are you using? What browser? OS X, Python 2.7.9. Please provide any additional information below. smacleod and brennie agree that this sounds like a bug.