In one of my courses, I get the following error at least once or twice every session when attempting to grade student work: after assigning a grade, writing a comment, and clicking save, a window pops up with a guy wearing glasses holding out his hand saying I'm not on the list as an instructor (or some such message). The grade is registered, but when I go to the next student and submit a grade, that same message pops up. When I have to sign out and sign back it, the problem is corrected. But, after a while, the error message comes back. I'm wondering if I'm being partially signed out in the background? But, the grade does go through, and I'm not kicked out of the system. I just get that popup window. Signing out and signing back in clears it up...until the next time it happens.