Regular? It’s constant on every recording, every camera and during live-streaming
It sounds like it starts a couple seconds in (after the vehicle passes).
Maybe try a factory reset on one, and see if that helps. https://kb.arlo.com/000062438/How-do-I-factory-reset-my-Arlo-wire-free-camera
If that doesn't help, your options are to
- exchange with the seller (if you are still within the return window)
- contact support (using the options in the app), and ask for replacement cameras
Exchanging is much less hassle.