China's big soy purchase
China can cancel and rebuy beans but at some point it has to be sure there are arrangements to keep the conveyor belt of beans to their shores full. The 'big purchase' from US supplies is completed before a major new price rise might occur at the prospect that Brazilian logistics will be the bottleneck for China's conveyor. Plan 'B', if you will. No doubt in my mind they were aware they might have to hedge bets. They did.
Considering China is importing nearly 60 MMT of beans this sale is only important in the sense that US supplies are limited. But they know we will deliver when needed. They will monitor Brazil's logistics which are likely to be deteriorating as roads get soupy and ship loaders at the ports fail.