Well, I’ve also read that he visited his mother in Indonesia some summers growing up. And that would have been his permanent address, since that’s where his parents lived.
If there was actually an Indonesian refugee office in Connecticut processing apps for foreigners, as another poster asserted; that’s the address that would have been on the paperwork that was sent to Baltimore.
Why would he do that? There would be nobody to visit. His parents didn't live there. His mother moved back to Hawaii in 1972
In 1971, Obama returned to Honolulu to live with his maternal grandparents, Madelyn and Stanley Armour Dunham, and attended Punahou School, a private college preparatory school, from the fifth grade until his graduation from high school in 1979.[19] Obama's mother returned to Hawaii in 1972, remaining there until 1977 when she went back to Indonesia to work as an anthropological field worker. She finally returned to Hawaii in 1994 and lived there for one year, before dying of ovarian cancer.