We have a 2013 rx350 fsport with about 500miles and 3 weeks old. Last week, the park assist started to falsely alert, front passenger and rear driver only. Brought it to the dealership, but the couldn't replicate the problem while there. Anyone else experience this? TIA

 

I don't have park assist on my current rx. But on my last car a Audi a6 had rear parking sensors. They started acting up and a simple cleaning of the sensor fixed the issue. Also rain can cause it give false alarms.

Later in my cars life the sensor had to be replaced because someone had bumped it in the city though you could not tell as I couldn't see damage to the sensor area. The service advisor took a magnify class and says he could see contrition. I declined the repair as the car was to be traded in. I just had the take the fuse out. In your case it should be warranty. Maybe make a video recording that always worked for Audi which is known for awful customer service.

 

Like triplecore said, they will sense mud, ice, and snow as well as people, carts, bikes, and other cars. Keeping them clean is the key.