It happened to me yesterday, I could not press down the release button all the way on the EVSE handle so the little hook latch that holds it would not release. I had to open the hood, remove the plastic panel and insert a long thin standard screw driver in through the side sort of to release the hook latch. For now I have threaded some wire around the hook latch so I can pull up on it to release it. I originally put a shim under the hook latch to keep it fro engaging when inserted but this doesn't work because apparently the switch inside the handle was still turning the power off.
When it first happened I was not sure exactly why it would not release, so I am grateful
for the information on this website which helped me figure out what the problem was so I could start dealing with it.
This is the panel under the hood I removed to release the EVSE handle hook latch
You need to release the little plastic fasteners by gently prying up the center head with a standard screw driver of a knife edge.
Then you can see the latch hook and lift it up with a standard screw driver.
This is my temporary fix