The state of California is investigating the safety of Tesla’s autopilot technology amid complaints from customers and company employees, according to reports from CNBC and other outlets on Wednesday.

The complaints are related to so-called “phantom braking” issues in Tesla Model 3 cars, where the vehicle’s autopilot driving function suddenly causes it to stop in the middle of the road. The “Phantom braking” trend in Tesla models prompted a federal investigation from the National Highway Traffic Safety Administration in early 2022.

Tesla owner Greg Webster reported the issue to the FTC in 2022, and a California attorney general’s office employee reached out to Webster about the issue earlier this year, CNBC reported.

In addition to the safety risks of an autopilot vehicle stopping quickly on a highway, Webster also said he felt misled by Tesla’s advertising, which is marketed as “full self driving.”

Despite being advertised as such, Tesla autopilot is not a fully autonomous driving system, which industry experts categorize as Level 3. Tesla’s system is Level 2, which requires a driver at the wheel ready to pick up driving at any time.

“Tesla should offer customers the option to receive a full refund of Autopilot features if they are unsatisfied with the product,” Webster told CNBC. “We bought a full autonomy product, and we received a driver monitoring product with partial autonomy.”

Tesla Model 3 vehicles use “Tesla Vision” camera technology to detect the roadway ahead of the vehicle and any objects that may be in the road. That’s a new, different technology from the industry standard of radar, which is common among other auto manufacturers.

More than 750 people have complained of braking issues as of mid-2022.

Tesla has not publicly acknowledged the California investigation, and The Hill has reached out to the automaker for comment.