Yeah, I've had this happen, too (if you expect one language and hear another one).
Another weird thing I have had is, after spending some time in Korea (about a week) and then going back to Japan, conversations by people around me sounded like Korean to me almost ALL the time. This happened to my wife, too - I think that one reason for this is that Japanese and Korean sounds are similar (in terms of "flavor"), as I don't get this for other languages that I know.