[Luckycharms]

This is pure speculation on my part, but I think it could have something to do with the combination of Volvo's design and the J1772 standard.

If you look under the safety section of the Wikipedia entry for the SAE J1772 standard: https://en.wikipedia.org/wiki/SAE_J1772
they mention how "The proximity detection pin is connected to a switch in the connector release button. Pressing the release button causes the vehicle to stop drawing current. As the connector is removed, the shorter control pilot pin disconnects first, causing the EVSE to drop power to the plug. This also ensures that the power pins will not be disconnected under load, causing arcs and shortening their life. The ground pin is longer than the other pins, so it breaks last."

So if that shorter proximity detection pin is not making contact, even if the "safety latch" is latched, no charging will occur.

You might be able to show this to your dealer, and if you can reliably repeat the problem, maybe get them to replace the charging input piece on your car.