Several key Tesla engineering managers working on its Autopilot semi-automated driving feature left the company after CEO Elon Musk told some employees he was unhappy with the progress in developing fully automated driving capabilities, according to one current and one former Tesla employee who have been involved in the effort. He is also upset that some team members have told him they can’t meet the timelines he has set for developing the technology, they said.

At least 11 members of the software team, or close to 10% of the total group, including some longtime members, departed in the past few months, according to multiple people with knowledge of the situation. Several of the remaining managers are now working directly with Mr. Musk. These departures follow Mr. Musk’s removal of the Autopilot group’s leader Stuart Bowers around the start of May, a move first reported by website Electrek, which also referenced some of the other exits. Mr. Musk also elevated other people within the Autopilot team as part of a broader shake-up.