Is Stanford's network traffic being routed through japan?

I'm on Stanford's network, and when using any of my machines, amazon asks me if I'm shopping from japan, and offers me the .co.jp version of their website.

I've tried different browsers, different machines and finally I tried using LTE, and got the regular amazon, without the option to switch to amazon.co.jp.

Should I be worried that my traffic is being routed through japan/is there an easy way to test for that? (I'm not actually worried about routing - routing would keep my ipaddress the same, and not give me this issue. I'm worried that something nefarious is going on, and I'm not clear on what I should call it, other than routing.)

As far as I can see, the only other alternative is that amazon thinks Stanford's ipaddress block is in japan.