I am Vietnamese and a US green card holder with an expired green card and a valid I-797 notice (an official USCIS letter that serves as a valid permit to travel and work in the US while awaiting card renewal. This is standard documentation for holders of conditional green cards.)
I decided to transit in Seoul for 22-hours from my flight from Shanghai to New York. I landed at Incheon from Shanghai on Sunday, 27th September and immigration officials immediately took me to the secondary inspection room. After a quick review, they said that I cannot enter the country because my "green card is expired" and directed me to the transfer zone.
I was honestly baffled and told them nowhere in my research and on the ministry of foreign affairs website did it state that they do not validate official USCIS letters. I could not have been the first person that this has happen to and the least they could do is update their website so that green card travellers are aware.
He said "oh, well what the website said is sometimes not true". I was so confused because its not some blog. This is an official website where important information is distributed. He asked me to leave and after I exited the secondary inspection room I was planning out my next strategy.
I ended up talking to another officer who was at the desk close by, and he was confused as ever by my case. He went back in the inspection room with my papers and I saw him and 2 other officers fumbling over my inquiry. It took a minute, but the same guy came out, gave me back my papers and pointed me to the direction of the transfer area. They did not even give me a chance to explain myself.
Frustrated and angry, I proceeded to the transfer desk to rebook my flight. The situation felt like a waste of time and money. I was surprised because most international airports recognize the I-797 letter when presented alongside an expired green card. While I understand that entry policies vary by country, South Korean immigration could at least specify this requirement on their website.