I have performed diagnosis on this issue and concluded that it's due to a Blink restart during charging. The blink EVSE will reboot for some unknown reason while leaving the contactor closed, and then when the pilot signal from the EVSE goes away, the Leaf's OBC will report a EVSE fault to the VCM. This causes this warning light, but it is temporary and will automatically reset upon a drive cycle once the Blink is disconnected.
You can verify that this is indeed the case by going into the blink's "Settings" menu and selecting "Device Info". Observe the "System Uptime" figure which should be the elapsed time since the errant reboot occurred.
This seems to occur less often in the newer Blink firmware. All Blink EVSE's should have firmware 2.1 by now, if they don't, it's probably because your internet connectivity is bad (Blink WiFi problem) or you have a defective SD card in the Blink. Call Ecotality and tell them you are having this issue and would like your firmware upgraded.
In the meantime, use one of our upgraded units
instead of the Blink if you have one. They will not cause this problem, and you'll have your intended charge each night instead of an unpleasant surprise in the morning!