In OTL, there's a communist rebellion in Madiun, East Java in 18 September 1948, following the resignation of the left-wing second Syarifuddin cabinet, after mass resignation of Masyumi (Islamist) and PNI (nationalist) minister as a protest to the signing of Renville Agreement. This rebellion is headed by Musso (senior communist, Indonesian delegate to Moscow in 1927 revolt. Also described by Wiki as Stalinist) and Amir Syarifuddin (Communist former PM), and was quickly crushed by Gen. Nasution with his Siliwangi Division. Musso and Syariffudin ended up dead
What if the whole affair end with Jogjakartan radio singing Internasionale? Say Nasution was succesfully influenced by Syarifuddin during his time in West Java (he, at one point, regarded former PETA with contempt and drifting into Syarifuddin). Or say Sultan Hamengkubuwono fell ill during that time, and can't influence Javanese to defy the revolution
Does if it succed USSR are willing to aid them? (Musso spent WWII in Moscow after all). Or it moves the Operation Kraai timetable forward? `(OTL it's in December 1948). If Operation Kraai moves forward can the USSR aid Indonesian diplomatically and/or militarily?