So I made one more run with the race route feature and want to share my observations with you, in case someone finds it interesting also.
To make it more understandable I list the runs first.
Run A was made before watchOS 9.2 released. It is my standard route for (about) 20km steady runs. When watchOS 9.2 was installed, this route was available with a date of Dec 9.
Run B was my first race route run on this route. It was a steady run and faster than run A. Did not update the race route.
Run C was my second run and a "fartlek" run where I ran 3km fast, 3km slower than my steady pace from Run A
Run D was my run today, again steady.
As reported in a previous post, I had to choose between two race routes on the same route:
First, the "legacy" route A from runs before watchOS 9.2 was released.
Second, a new route from runs B and C (recognizable through personal bests and last run coming from B and C)
Run D was run against second race route and afterwards updated. So I still have two race routes on the same course afterwards. Legacy route still shows data from Dec 9 and is not updated.
Observations:
1) I my previous runs I was wondering what the flat grey bars mean. Today with the newly created race route, I had a fully understandable elevation chart that showed about 1km of the route and even in my almost flat area showed every bump in the road. Excellent! At the end of the run, the behavior was the same as when racing against the legacy route. About 200m before the end of the route, it showed the entire elevation profile of the run.
2) As I was running steady pace, it was clearly visible where I was faster in run C and where I was slower. The "behind" "in front" was behaving perfect!
So, to conclude: running against legacy routes is not ideal when you want to utilize the elevation chart.
Also, there is a clear bug that legacy routes are not updated or deleted. After two subsequent runs on a route, Apple creates a new route and afterwards updates this new route.