Hello James,
It looks like the data isn't being retrieved from the Citdael historical database. If this was working before, and now none of such graphs update, I would try to query Citadel from, say, the MAX.
Can you see data in MAX (under Historical Data?). If yes, I would then create a test VI with a graph and invoke the HMI Wizard on it to quickly check if this works.
Also, if your DSC Engine is running when this happens, you can bring up the Engine Manager and click the Show Events check-box to see if there's any reference to the Historical logging being turned off.
I hope this at least gets you started in troubleshooting the issue.
Good luck!
Khalid