I have already reported and noticed that i suspect that climb guidance is based on « distance from start » of the route instead of « current gps position ».
My feeling is that if I start a climbing section witch start at 25km from start of the route, and if the watch has already mesures 25km few meters before the gps point where the climb was supposed to start, then the climb guidance for this climb willl start at the 25km point mesured by the watch.
From my experience the further you are in the route, the most is guidance « delayed ».
But I have never take time to really verify that feeling, I may be wrong (@isazi i remember you said to me that I was mistaken about the behaviour).