[techsupporter]

> And while we are at it stop tunneling my data back "home" when I travel. I don't want increased latency.

You might not, but a whole lot of customers who aren't as technically sophisticated did. When T-Mobile first started doing included international data roaming, they didn't tunnel back. That caused a lot of confusion from customers who didn't realize why stuff they expected to work, like checking their bank balance, didn't. (It also made throttling speeds a lot more difficult.)

So to fix that, T-Mobile tunnels you back to a few endpoints in the States. Banking apps are generally happy, as are Netflix and Spotify. Most customers are happy because their phone "just works" the same as it "always has".

For those of us who want to avoid the latency, we get a local SIM for data (if possible).

[hunter2_]

This is interesting. I use Verizon Wireless from the US, and when traveling abroad on their travel pass (roaming), some large multilingual websites serve me the local language instead of English, on sites that serve me English when I'm at home. My browser (Accept-Language header) is configured for only English. I always decline location API browser popups.

The only thing I can think of, assuming they tunnel as you describe, is maybe I first loaded the site from local WiFi instead of mobile data, at which point I was redirected (to a localized subdomain that doesn't redirect back) or got a cookie or something, which lingered as I continued without WiFi.