IANAArchaeologist but everyone should take this paper's main conclusion with a huge grain of salt. There is a lot of nuance to radiocarbon dating and I think th

IANAArchaeologist but everyone should take this paper's main conclusion with a huge grain of salt. There is a lot of nuance to radiocarbon dating and I think there are several problems to their methodology. They use the generic SHCal20 calibration curve for the southern hemisphere which is generally fine for testing bone and some plant matter but they didn't find any fossilized plants and I doubt it's accurate for soil samples in a volcanically active area. Gunung Padang sits atop an extinct volcano and Mount Gede is miles away uphill with active vents and hot springs. Local emissions of C14 depleted carbon dioxide and dissolution of ancient carbonate minerals in groundwater usually throws those numbers way off. The samples will appear older because the volcanoes are constantly dumping C14-poor carbon into the environment from deep in the earth. There's ample evidence for their other conclusions like the multiple stages of building but they'd have to corroborate the radiocarbon dating with several other methods and create their own calibration for the region to really confirm the dating, which isn't necessarily an easy thing to do.