Another problem we are experiencing, and I think it is related to the custom visuals, is on the iPhone app, after I have openned one of the dashboards with custom visuals, if I try and open another dashboard (or even if I try and reopen the same one), it just hangs - I get the loading spinner and nothing appears. I have to kill the mobile app and start again.
Does this happen for you as well? It started happening the same time as the issue with the custom visuals.