A few notes:
- It is good the temperature safety shutoff of the EVSE worked!
- That circuit should really of had a 16A breaker to start with as a dedicated circuit with a socket designed for 16A. I've got effectively got the same setup - wired for 3-phase 32 A, but only have a single phase 16A socket currently connected and have a 16A breaker.
- No guarantee that the current measurement of the EVSE is accurate. I've found differences upto about ~12% compared to my Fluke.
- I believe the charger can increase current (upto max current as set by EVSE duty cycle) to reach 3.6 kVA. So a voltage drop could potentially increase current, although I think the EVSE also detects voltage drop so this should throw an error.
In any case, the EVSE likely has a fault here. Either the plug wasn't up to spec, or was allowing more current than it should. Technically could of also been a problem with the socket.