[Observium] Strange issue

Hi folks.

I've been noticing a strange issue when using Observium in the last couple of days which has me scratching my head.

Occasionally, when I am browsing devices, or device components, I'll get a graph or image which just comes up reading "no authorisation" or similar - and anything else I click on results in my being kicked back to the logon screen.

I don't *think* it's an inactivity timeout - at the times I have noticed this happening I specifically noticed it because I was in the middle of doing something.

Is there something else I could have misconfigured which would cause this behaviour?

Thanks.

DaZZa