@Dimitrios-Kanellopoulos
I guess there’s something we never found before about this issue. So, maybe it’s something new/recent.
Today, I started a new trekking activity navigating a route already on watch and selected before starting. At a certain point I’ve seen that the graph was frozen. What a mystery!
While on the summit I decided to switch to a brand new route, so i created it, transferred it to the watch, did the BC trick and resumed the activity.
The graph was working as expected, but when my pal wanted to extend a bit the trip, we took a detour and at that point I’ve got the usual “off route” message and after a bit I’ve noticed that the graph froze.
So I reminded that at the beginning we took a shortcut so we went “off route” for a while.
My suspicion is that, if we stay for some time “off route” the altitude graph get stuck even if we go back on track.
The BC trick obviously works