This is an announcement from China’s Ministry of Commerce: Link.
This is a customs consultation response regarding export issues for related products: Link.
It may also explain why many AliExpress magnets have stopped being exported. It could be due to concerns about risks from Sellers or their logistics service providers.
Since Maker’s Supply hasn’t delisted magnets and trade war tensions are easing, I guess their magnets may only face customs checks, but I don’t think there’s a risk of supply interruptions.