While I would love the extra credit for saying it's intentional, we believe the Alliance Perk may be granting more National Trade Goods than expected.
We are investigating it now.
Until then, enjoy earning multiple National Trade Goods!
Victory chests are still bugged with NTGs. I'm only getting an offer of 1 NTG, but I have the library research for +1 goods, so the minimum I should be offered is 2. The 2+ behavior was always the case before the server issues.