If I read the OP correctly, the issue is the meaning of the frantic beeping, and to that issue, as a Bolt + Varia RTL515 user, I’ve experienced the same, but only in the busy, urban setting. I think what’s happening is that the stop-go-slowing-turning activity is causing the unit to bunch up the various alert tones. I don’t think it’s abnormal behavior at all, nor indicative of a problem, although it is annoying. In less dense and heavily trafficked environments, my 515 works perfectly despite the in-town frenetic beeping.

Many reviewers have noted this behavior, and until Garmin can introduce some kind of filtering to prevent it, perhaps location information, the “fix” is to switch off audible alerts while riding in the city.