Yes, it’s one of those stories that because we think it’s true it tends to get made true. Because it’s assumed that those of Asian heritage are really good at maths, they typically put more effort into maths and are more likely to pursue maths than others, and so the belief gets made the reality but not for the reasons people think i.e. some genetic or cultural advantage.

It’s similar to how people born in September for example, are more likely to succeed in sports and pretty much everything. At first glance, you would think it must be some mystical thing about being born in September, but in fact they are simply more successful because that is the beginning of the school year and so they are older than the other students, giving them an advantage, and so people believe they are better and so give them a better education than people born in later months, which gives them better training and so they end up turning the illusion into the reality.

If you’re interested, you may find the book Outliers, by Malcolm Gladwell to be of interest.

Anyhow, thanks for reading! Much appreciated :-)