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I had this issue with just the driver side camera alerting at random and started logging the date and time the alerts showed up. This made my case to Tesla more compelling and they diagnosed the issue as a faulty camera and replaced it.
I too get inconsistencies where it would stop right after it started but it never went off with a Honk like that. Maybe contact support and see if that's normal? They should be able to pull logs from your car to see what triggered the event.