I already created an issue on the tracker for this, but I thought I'd post here as well to see if anyone had experienced a similar issue or could provide some insight.
Any time a user tries to click the "Add submission" button in any assignment, we're receiving the error "Invalid response value detected". Changing settings on assignment, course, and user does not seem to have any effect. Users are able to access quizzes and discussions without errors.
We do have the Poodll feedback plugin installed, but we're receiving the error even when disabling that feedback method for a particular assignment.
Any thoughts on further testing we can do to get a more detailed response from the system?