One of EV startup NIO’s cars got stuck on a highway in China on Wednesday after the driver triggered an over-the-air software update, according to Bloomberg and the South China Morning Post. The driver, who was testing the car, and a NIO representative were wading through Beijing’s notorious traffic when the update was triggered. They wound up inside for “more than an hour” after the process began, SCMP says.

The NIO representative who was stuck in the car said on Chinese social media site Weibo that “[p]olice officers came, one group after another, yet we could not even wind the window down,” according to SCMP.

NIO apologized on Weibo, according to Bloomberg. The company said in a post it will “optimize” the confirmation process for over-the-air updates going forward, and reminded customers that they should only accept an update when the car is parked in a safe place.

NIO says it will “optimize” the update process going forward

The car was stopped in traffic when the driver triggered the update, a spokesperson for NIO told The Verge in an email, but it should have been obvious what was about to happen, they said. “Before users start to upgrade the software, they receive a clear notice explaining that users need to park their cars during the upgrading and the car’s relevant functionalities will be shut down,” the spokesperson wrote. “The upgrade takes several steps, including entering the password and confirmation. The user tried to engage the upgrade while she was caught in a traffic jam.”

Cars have evolved rapidly in recent years with the addition of touchscreens, complex user interfaces, and even advanced driver assistance features (like Tesla’s Autopilot or GM’s Super Cruise). The software at the heart of these advancements can cause new kinds of problems for companies of all sizes. Last February, for example, an over-the-air update from Fiat Chrysler sent the Uconnect infotainment system in some of the company’s cars spiraling into an endless boot loop, a problem that left a few owners with dead batteries. Tesla, meanwhile, issues so many over-the-air updates to its cars that it started to mess with some owners’ heads last summer.

NIO is just one of the many high-profile EV startups that have emerged over the last few years, but it’s also one of the only ones to have started delivering cars. The company’s first model, the ES8 SUV, began shipping last summer in China. More than 10,000 were delivered by the end of 2018. NIO is also publicly traded in the United States, and the startup plans to bring its electric cars stateside in the next few years.