It seems like it's getting worse, but probably just me noticing it more. The RCT715 is "losing" an awful lot of cars. Two things cause this to happen; thing one is when a car comes up from behind and then "paces" me for a while. The RCT715 apparently thinks it's a bike riding with me. It's very disconcerting that you get a green lane with the all-clear beep when this happens. And in the city, it happens a lot.
The other occurs on windy roads, where it picks up the car from quite a distance away (obviously when there's line of sight visibility) but loses them (and goes to all-clear) way too quickly. The garmin can tell when you're on a windy stretch of road; the software should allow for a longer period of time before giving the all-clear on such windy stretches