The New York Times write-up on this is pretty good: https://www.nytimes.com/2025/09/05/us/georgia-battery-plant-.... This plant was under investigation for a significant time. Some citizens and workers with visas were initially detained, but were released once their documentation was verified. The workers being deported were not Hyundai employees, and it seems clear from the company's response that they were not working in the U.S. legally.

https://archive.is/NfaBw