Thank you, you're right! It definitely seems to have a problem when the end of the string ends with 다. It seems to work if you end the sentence with "다." instead of "다". I'll look into this more. There should be plenty of "다" data in the training set, maybe there's something deeper going on.
Ah yes, I'm well aware! My company (hiworker.com) makes AI products for ship building and construction companies that have a large foreign workforce. We have some customers in Ulsan. It's a beautiful place, I love visiting.
PS: I saw your feedback report. 화이팅! :)