Notice something about the sheet for stamps KPC3331-3334? Look again. And then again. It’s really there. Yep, it’s a typo. Look at the first English sentence: “indepence”. Very understandable typo, can happen to anybody. So I emailed the philatelic agency and told them about the error. They emailed back after a couple of days, telling me they had also found the mistake and they had changed the text already.

Which is why they sent me the new version of the sheet.

Oops. Now it was no longer a typo, it had become a full blown translation error. However, this one is also very understandable. The problem is that in most Korean dictionaries (even the new online ones, such as Google Translate) there is no difference between “independent activist” and “independence activist” when translating the English term into Korean. In both cases most dictionaries will for both cases show “독립 운동가” as the Korean translation. And it seems the wrong option was chosen.
By the way, to show this the other way around: perhaps a better translation of “independent activist” would have been “독립적 운동가”. If that had been included in dictionaries the Korean postal services would not accidentally have run into this mistake but chosen the only correct translation for “독립 운동가”.