The past year has been a time of intense activity for some employees at the Santa Clara headquarters of Seres, a Chinese-owned, Silicon Valley–based electric car maker once described in U.S. media as a Tesla challenger. One worker built a Lego Star Trek spaceship at his desk. Others played pool, foosball and UNO for hours. Some watched movies or shopped on Amazon all day. 

Then there were the productive ones who took online M.B.A. courses or launched their own freelance consulting businesses. What these employees did not do was the work for which they were originally hired: to develop electric vehicles for the U.S. market and sell them to American consumers.