They said Korean terminals have the chip in a slightly different location to UK cards. They took my card and slot it into the terminal, but I didn’t have to key in my PIN I think. At least the second time I didn’t have to. Usually they take your card and insert it into their end and if you have to key in your PIN (on Singapore for NETS) it’s on a connecting terminal that your card isn’t slotted into. I don’t really know any technical language so I can’t explain this properly, but that was the clarification I was told when I asked COps. It worked the second time so I didn’t question it any further.