On the other side of this, I’m white as they come, born and raised in the Midwest by very white parents also born and raised in the Midwest.
People ask where I’m from way way more often than they should, in my own home state. Where I spent all but 5 years of my life.
I have no clue why, but they don’t think I’m from the US.
Some possible related things -
When I was a kid people used to tell my mom I look “exotic” and I still don’t know what that means in relation to my appearance; I look like everyone in my dad’s family.
I spent a couple years in California and a couple years in Texas, and learned Russian, Spanish, and Japanese (and a spattering of phrases and grammar from other languages, almost none of which I remember), plus consume a fair bit of foreign media. But I don’t really think I picked up accent features, at least none I’ve had anyone able to pinpoint.
Either way, that conversation always turns into a slog of “there’s just something that tells me you are from somewhere else, are you sure I’m wrong???”