I don't think that matters.Due to a number of rulings by the SCOTUS in recent years it's very difficult for one to lose his/her US citizenship short of formally renouncing it before an official of the State Dept.It used to be fairly easy to lose it but not in the last 40-50 years.The Federal courts have,in recent years,upheld the concept of "dual citizenship" for US citizens,so being recognized by Indonesia as one of its citizens would not jeopardize his US citizenship.I could go on but I'll spare you the details.
I thought I read somewhere that Indonesia did not recognize dual citizenship and that to travel as an Indonesian citizen, after the age of majority, on an Indonesian passport, one would have had to renounce his American citizenship.
Anyway to look up what the requirements were for Americans traveling into Pakistan when Obama was traveling? I know there was alot of turmoil.