Based on all the above it must be some kind of software issue. I'm installing the 2020.36.11 update right now to see if that does something. Otherwise, the only thing I can think of is that it's some kind of software issue. If I could get someone to plug their Tesla into my charger and have it work I could rule out the charger. But based on the fact that the same thing happened with the mobile charger, I'm pretty sure it's fine.
Have the new software installed. Problem seems to persist. It seems Tesla is hot pushing 36.12 to the Y (via cell) could be rolling out a hot fix for this in waves but let's see. In the last day we have seen 10ppl post same issue in the M3 threads. It feels like a software bug with so many suddenly experiencing the same issue.