The Hyundai HQ is in South Korea, you can expect that they will bring people from their HQ to oversee their operations and to do knowledge transfer. It is common sense.
Sure, but that doesn't seem to apply here whatosever. 475 people isn't 'knowledge transfer.'
Honestly this could be a simple as "all the docs for how to do this are in Korean, and doing the job effectively involves communicating with HQ in Korean."
It can be, the plant just opened and they hired thousands of people.