Chinese drone giant DJI Technology Co. built up such a successful U.S. business over the past decade that it almost drove all competitors out of the market.

Yet its North American operations have been hit by internal disturbances in recent weeks and months, with a raft of staff cuts and departures, according to interviews with more than two dozen current and former employees.

The loss of key managers, including some who have joined rivals, has compounded problems caused by U.S. government restrictions on Chinese companies, and raised the once-remote prospect of DJI's dominance being eroded, said four of the people, including two senior executives who were at the company until late 2020.