On April 23th 2019, GM Technical center Korea finally decided strike. GM Technical center Korea is is the new corporation for R&D which has been separated from GM Korea. It’s responsible for research and development, design.
You can see more detailed news article in English here :

http://koreajoongangdaily.joins.com/news/article/article.aspx?aid=3062242&cloc=joongangdaily%7Chome%7Cnewslist1

http://koreabizwire.com/gm-koreas-rd-workers-vote-for-strike-no-output-losses-expected/136333

http://www.koreaherald.com/view.php?ud=20190423000841