>>I'm getting this several times a week, and I think it's been like this for a few months. Didn't run any statistics, assuming there's sufficient logging on the server. Happens usually while I'm away, when automatic refresh tries to reload the menu.
>>
>>See the image.
>
>Same here - usually happens overnight

Your night is 7 hours later than mine... which leaves a lot of time when it can happen. I'm sure Michel logs any navigation to error page.