Well I also speak from experience
Maybe it feels good for you because you get that attention when you are in Korea? I mean, I'm not even sure I would take it as a compliment if someone appreciated my swedishness here in sweden, but abroad it makes you feel a bit special right?
So if I go to korea, get a korean gf and let her know how I have a preference for koreans and how much I adore them it wouldn't be that strange if she started getting jealous and unsure of how trustworthy I am.
Once she starts thinking about why she likes you, that thing is always going to hang over if it's something she has been made aware of.