Yep it’s true. I live in Taiwan. Non-white native English speakers are assumed to not be American, Canadian, British, Australian, etc.
One of my job interview questions was “how would you react if a parent didn’t think you were a native English speaker?”
Funny enough, there are a lot of white and other non-black South Africans here, so I know they must confuse a lot people too because it’s assumed that only black people are from Africa.
When I first came to my school, it was me and a blond South African who were the new teachers. The staff thought she was the American and I was the South African lol.