Interesting to see your repair. Your car has Polish number plates, so I assume you are in Europe.
But your car has an American OBC, so presumably this car is an import from the USA.
( I am amazed it is cheaper to transport used cars from the USA, rather than just buy used from Germany. But as we have seen in the Jordan thread that is the reality.)
For an example of this American OBC see - OBC Failure in USA - Charging Fault error thread.
For an example of a European OBC see - OBC Failure in Spain - Charging Fault error thread.
We have always assumed that the main difference between the American and European OBCs was that Europe uses a higher domestic voltage 220V/240V than elsewhere 110V. But what the difference may be is not obvious, and cannot be seen by owners.
What we did see is that the European OBCs were always software limited by about 10% under the stated 6.6kW output.
American cars in 2014 and 2015 did not have this restriction.
As the original OBCs failed, or cars were called in for the OBC software update almost all cars now have the software limit.
How do you read the version numbers on the OBC firmware?
What I have seen is the ROM ID.
Here's the display from Kia's KDS tablet showing the original (top) and latest ROM ID (bottom).
The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.