I've had a ClipperCreek HCS-40 EVSE for my Bolt since January 2017. The original unit started failing two months after I bought it: when I plugged the car in, it would only charge for a second or two, and then the EVSE would sit with flashing warning lights for a few minutes, "thunk"-ing the relays occasionally. That would happen repeatedly for a few minutes, until it eventually worked (which always happened after a short while).
I contacted ClipperCreek and they diagnosed it as "patina buildup on the contactors". It apparently makes the safety systems kick in because of higher-than-expected resistance over the contactors until the car has drawn enough current for a few seconds to "burn off" the patina and lower the resistance. (I may have the technical details wrong but that was roughly it.)
Since the EVSE did eventually work every day, albeit with a few minutes delay during this process, I was afraid they were going to tell me "yeah, that's not covered under warranty because it still works". But they asked for my postal address and sent me a new one right away, and I sent the bad one back in the same box. No charge.
Fast forward almost three years. I'm a month before the end of the three-year warranty, and the "new" unit has started doing the same thing. So I talked to them again, and same deal: they are immediately sending me a new one free of charge. (They also said the newer units have a firmware change that prevents this problem from happening again.)
I totally understand that bad things happen, but I'm impressed by how they handled it when it did. I saw someone else on Reddit say "was having trouble with my 5 year old Clipper creek evse related to patina build up. It is out of warranty but they are going to service it and update the firmware for free", too, so it's not just me.
Anyhoo, if anyone is wondering where to buy an EVSE from, ClipperCreek gets my vote. The thing has been completely reliable aside from this, and seems well made, too; it's industrial strength.
(I'm not an employee of ClipperCreek etc. Just a happy customer.)