2-4-x Forums with post-2.4.0-001 gradebook.
When a student goes to Forums in a course site that also has Gradebook, this error appears in the app server logs:
ERROR: AUTHORIZATION FAILURE: User c689f313-6789-4e36-80fd-8dc1653cbce5 in gradebook 264d249e-a6d0-480d-80e8-b5f35bd0166b attempted to get assignments list (2007-07-09 15:59:38,334 TP-Processor34_org.sakaiproject.component.gradebook.GradebookServiceHibernateImpl)
However, no error appears in the UI for the student.
Presumably Forums is incorrectly calling the Gradebook service. However, the Gradebook service should probably also log this as a WARN rather than ERROR, as it's not an error per se.