Index: lib/accesslib.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/accesslib.php,v
retrieving revision 1.524
diff -u -r1.524 accesslib.php
--- lib/accesslib.php	20 Oct 2008 13:47:08 -0000	1.524
+++ lib/accesslib.php	22 Oct 2008 07:59:13 -0000
@@ -1332,6 +1332,11 @@
         $rs->close();
     }
 
+    // MDL-16963 in the COURSE case, role-assigments were being duplicated.
+    if (isset($accessdata['ra'][$ra->path])) {
+        $accessdata['ra'][$context->path] = array_unique($accessdata['ra'][$context->path]);
+    }
+
     //
     // Walk up and down the tree to grab all the roledefs
     // of interest to our user...