The patent owner can get their products produced where ever they like. Just because you have it made in another country, does not mean that country then owns the patent.
then you obviously have no idea how joint venture works in china.
no company can go on its own in china, they HAVE to partner with a Chinese company, and when production is involved (especially of tech china does not have or own) then a certain amount of tech sharing IS REQUIRED.
so, they dont own the patent, but then, the basis for how that patent works is pretty much given for free to china.
AMD gave them Ryzen tech for instance. china is abusing the fact that they have a 1.4B market, that makes all managers in big companies have a hard on just imagining how much money they will make in china. so, they accept abusive clauses china provide them with.
Do you know what happens next in most cases? the Chinese "partner" that got all techs from the foreigner, start to ramp up their own Chinese products (or sell the tech to other Chinese companies) with acquired techs, sometimes improve upon, make the same or copied product as the foreigner, but for a fraction of the cost because they lower quality where possible and they obviously did not pay shit for R&D.
then they basically steal the market share from under the foreigners, and foreigner having nothing left can only leave Chinese market.
Doing business with china was in most cases was and is a bad idea, most of what china has to this day is "stolen" tech. They did improve upon them sometimes, but they did not pay or invent the tech in the first place, and the way their patent work means whatever was patented in another country but is not in china is basically not patented, so a chinese company steal the tech, apply for patent in china and bam done.
there is a huge list of countries having issues with the WTO filing claims against china, because in many cases china just uses techs without ever paying royalties to the inventing country, but WTO are rarely fairly enforced by china. they just get away with pretty much anything.
from WTO website :
In August 2020, China's Supreme People's Court decided that Chinese courts can prohibit patent holders from going to a non-Chinese court to enforce their patents by putting in place an “anti-suit injunction”
so basically, that means china SHITS all over patent holders worldwide, Chinese company can use whatever patent they want, not pay shit, and have the international company unable to sue anywhere BUT china, and guess who Chinese courts side with in 90%+ of cases... yeah you guessed it, Chinese companies.
so take the 2 things together... china gets patents for free, and use the ones it doesn't own for free. and no one can do anything about it.