RTL515/Forerunner 965 connection issues

Just got the RTL515 and paired it to my Forerunner 965 which I use as my bike computer when cycling. But after one ride the connection is inconsistent. Sometimes is shows the graphic on the right side of the watch illustrating the approaching cars, other times I just get a pop-up message at the top of the watch saying a car is approaching but no graphic. Also, the little icon indicating that a radar is connected is sometimes displayed, sometimes not. Seems that when it's displayed I have a "full" connection and get the graphic showing the approaching cars, when not displayed I only get the pop-up message. I rode for about two hours and the unit switched back and forth consistently between these two modes the entire time. I wasn't able to discern any other factor that would be causing a change, it just seemed random. 

Thank in advance for any suggestions!