Foreigners smell blood in the US housing market. Remember, these folks made their money in Russia, Latin America, Asia, etc. etc. because they are smart. They are much more used to detecting crises than Americans.
Wealthy Mexican immigration really started in earnest in 1982, with the Peso devaluation that year. There are more wealthy Mexican and South Africans et al. in San Diego than many people on this forum believe, apparently.
A few friends of mine (Eastern European) have been bargaining hard recently, and are still unable to find a buyer that they feel “gets” it. This is at the very high end of the market, so that sector will also likely be affecting by the housing slowdown
So far, the stubborn sellers have found buyers, but it is early on, and this in the high end.