Varia 515 disconnects

That is an error code being sent from the radar unit to indicate that has hit a signal saturation issue. The Radar will clear the issue automatically, but the warning message does need to be manually cleared. 

I've connected a Bryton Gardia R300L to my Edge 850 and I have the usual disconnects that I always seem to get in the same geographical areas. Nothing unexpected there. However, there's no error code associated with those disconnects/ reconnects. It just reconnects after a few moments without issue.

Can you explain what signal saturation is? And if it disconnects and reconnects, what's the benefit in telling the user and why does a user need to dismiss the alert. It would make sense if there was an error that was actionable or had some value to the user e.g. Battery is low. 

The error code is sent by the radar so I assume the Bryton is just failing silently. I'm guessing Garmin sends and displays the error message for safety/legal reason as the radar is temporally none functional and is a safety device.

Saturation is receiving too many signals back, typically due to a highly reflective surface.