MORAINE, Ohio — When a giant Chinese glassmaker arrived here in 2014 and began spending what would become more than a half-billion dollars to fix up an abandoned General Motors plant, it seemed like a tale from opposite land: The Chinese are supposedly stealing American jobs — as no less an authority than President Trump has pointed out.

But now the Chinese were suddenly creating them. More than 1,500 jobs, in fact.

The Chinese company, Fuyao Glass Industry Group, decided the money was worth spending in this Dayton suburb to be close to its key customers, the big American-based automakers that buy millions of windshields each year.

And it was not alone.

From 2000 to the first quarter of this year, the Chinese have invested almost $120 billion in the United States, according to the Rhodium Group, which tracks these flows. Nearly half of that amount has come since early 2016, making China one of this country’s largest sources of foreign direct investment during that time.

But with the explosion of investment has come unexpected trouble. At Fuyao, a major culture clash is playing out on the factory floor, with some workers questioning the company’s commitment to operating under American supervision and American norms.