San Francisco neighbors who live in a building next to a Waymo parking lot are still being haunted by overnight honking. That’s despite a fix from the ride hail company that seems to have fixed the original problem — the cars beeping their horns in the parking lot — but has also revealed that the issue is a little stickier than it may have first seemed.

Waymo said last week that the honking was the result of a safety feature triggered when a Waymo car detects another reversing toward it. Sophia Tung, who runs a YouTube livestream of the lot, told The Verge in an email that the first night after Waymo’s patch, several of the cars missed the parking lot and inexplicably entered a cul de sac next to her building. In a video we viewed, the vehicles became backed up in the cul de sac and started honking.

Tung said the company quickly “disabled the cul de sac completely and threw us an ice cream social to smooth things over.” Things were quiet for a couple of days after that, she added.

But early this morning, the robotaxis revealed another edge case when enough returned at once that a line formed to get into the lot. After one of them reversed toward the others waiting out on the roadway (where they’re seemingly free from the tyranny of the lot’s restrictions), it set off a chain reaction of Waymo vehicles each backing up, triggering the next one in line to honk and drive backward, and so on.

Tung said she’s already reached out to Waymo about the new round of honking. She also has plans to talk with Waymo product management and operations director Vishay Nihalani on the livestream tomorrow, starting at 5:30PM ET.

Waymo did not immediately respond to our request for comment.