I don't have any info on the new OBC, sorry.
However, I do have a new update. My car just had the same error show up again today and it's being towed back to the dealer :-(
I received the "External Charger Error" message on my navigation screen last Friday just after starting the vehicle and the vehicle was not plugged in for a few days.
The car was towed 160 miles to the nearest EV certified dealer in MA because there are none in my home state of ME. Kia roadside...