They seem to have figured out that US Dollar hegemony is coming to an end at a faster and faster pace. That the Saudi's rejected Biden's pleas to increase and then actually reduced oil production was certainly an insult but then we threatened to pull our missle defenses out of their Country and threatened anti monopoly protections. Since then they have agreed to a Russian defense pact and joined the BRICS nations while now allowing payment for their oil in Gold backed Yuan bonds and are working out bilateral deals in many currencies. I think it's safe to say they don't like us anymore. Why would they like us when our 'Netzero' fossil fuel policy is antithetical to their Oil businesses. All this courtesy of "the gang that can't shoot straight" in the White House. Result: The PetroDollar is wounded badly as is the US Dollar's position as the World's Reserve Currency. We will pay a terrible price for this ineptitude in the future all because we choose not to increase production and drive prices down around the World which we could easily do.
Link: https://www.zerohedge.com/geopolitical/foreign-central-banks-continue-dump-us-treasuries