The F12 thing didn’t work for me. Ctrl + F5 seems to work.
I probably should have said this earlier but,
at my building, we have a stand-alone fog server. The bandwidth chart for it works perfectly as expected.
At our administration center, we have a large fog setup. The main server has two storage nodes defined for it, and there are 14 other storage nodes that are elsewhere but managed by this main server. Only one of the main server’s storage nodes is “graph enabled”. All other remote storage nodes have their graphs disabled. This is the system with the graph issue.