This is not new,
it is already implemented for years to prevent players to send resources to inactive farms using sitter accounts and pickup with your own. Used to be common way to avoid limits...
2016/2017 i saw it first time i think.
Didnt know about the trading restriction, but obviously the resources originate from account that has same ip logged (as sitter) as the one raiding.
Pretty sure shipments via market trade were always excluded. Text was also different so I bet on undocumented change, not a bug or mistake.