Zoox, the Amazon-owned robotaxi company, issued a recall after one of its self-driving cars blundered into a cloud of heavy smoke near a fire scene that emergency workers were responding to, and became confused.

The recall, in the form of a software update, will affect its entire fleet of 105 autonomous robotaxis. 

The patch “enhances the existing capability of detecting active [emergency] scenes by adding the ability to detect and respond to heavy smoke in certain situations,” Zoox told TechCrunch in a statement.

While you wouldn’t be remiss for thinking this was related to the wildfire smoke covering much of the eastern US right now, the recall highlights how self-driving cars still struggle to respond to unpredictable conditions.

In a report filed with the National Highway Traffic Safety Administration, Zoox said that during the June 20 incident, one of its robotaxis “encountered heavy smoke that obscured an active emergency fire scene that was not cordoned off with cones.”

Though it should have avoided the smoke cloud, the vehicle, which wasn’t carrying any passengers, “braked hard while attempting to steer away before coming to a stop,” the company added. Eventually, a teleoperator took over the robotaxi and manually reversed it away from the scene, allowing first responders to place traffic cones to block off two of the three lanes. CNBC reported that the incident occurred in Las Vegas, where Zoox is currently offering free rides.

It’s not the first time robotaxi companies have landed in hot water for impeding emergency responders. 

San Francisco Police were forced to help move immobilized Waymo robotaxis that piled up in roadways in intersections during a city-wide power outage last year. Emergency responders complained they’d become glorified “roadside assistance” for the vehicles. In March, a Waymo robotaxi blocked an ambulance from responding to the scene of a deadly mass shooting in Austin, Texas.

These mounting incidents led NHTSA administrator Jonathan Morrison to send a strongly-worded letter to robotaxi companies, calling their cars’ interference with emergency responders “unacceptable.”

“Let me be clear: the inability to detect and appropriately respond to such situations represents a functional insufficiency,” he wrote. “Emergency scenes are not rare or extreme ‘edge cases.'”

“To state it bluntly: an AV that cannot safely interact with first responders is a danger to the general public,” he added.

More on robotaxis: Robotaxis Are Turning Passengers Into Horrible and Entitled Menaces to Society