There most be different data sets or different measurements, or categories of bonds being used. E.g.
https://www.bloomberg.com/news/articles/2024-01-16/china-bon..."Global investors raised their holdings of Chinese bonds for a fourth straight month, capitalizing on a lucrative currency swap strategy to continue their gradual return to the world’s second-biggest debt market.
They bought 181 billion yuan ($25 billion) of local yuan bonds on a net basis in the country’s main interbank market in December, taking their total holdings to the highest since April 2022, show Bloomberg calculations based on clearing house data."
All of this is besides the point that foreigners are buying China's bonds, as @loeg has stated. They are essentially swapping out riskier equities for the safety of bonds which is by and large what is often taught to do when the economy isn't booming, only to switch back into equities when the downward cycle is over.