I was stuck in some really bad traffic yesterday, but the map always showed blue lines for the route I was on. Tried turning the live traffic display on/off a few times, but that didn't help, neither did pinch/zoom. Not yet on v9, still on 36.2.
I find them to be somewhat live it takes a while for the maps to update the traffic but they do eventually, not sure how they get the info i.e. sensors, traffic cams, users etc
I've found the Tesla nav to detect traffic problems and suggest a re-route before waze does. Increasingly I compare the two and Tesla nav wins for accuracy.
Hmmm ... that has not been my case. Fortunately, I have Google Maps on phone ... don't think the Tesla nav has ever suggested a reroute, come to think of it.