The charge before last, the graph (as seen in the apps, on iOS and Android) abruptly dropped off after a few minutes, but the charge completely normally, AFAICT (almost a full charge, over five hours). Then, last night, I fully charged the car, and it never showed up in the apps at all -- in fact, they said the EVSE was "Offline" and was "Last seen: 3 days ago". Since it is still charging, I wouldn't mind so much, except that I was unlucky enough to get the last version of the JuiceBox before they added indicator lights, and of course it's a little hard to see when the i-MiEV is charging, and now I have no remote charge tracker for either car or EVSE. Time to dig out the warranty, I guess.
I wonder if it's lightning-related. We had a couple of momentary power outages recently -- mostly harmless, but each time, it left the EVSE making a high-pitched noise, until I unplugged it (from the wall; it wasn't plugged into the car).