Why do you draw them as separate railings? You know a railing can have more than one segment, right?
Sorry, I did mean seperate type of railings with seperate types of endings.
The railing in the photo below is indeed one railing with 3 segments.

If I cannot set the non continuous railing shorter than the railing, why doesn't it react the same?
Why doesn't it fillet (or am I missing something = what am I doing wrong)?
Draw as one railing with two straight segments and a curve segment.
This was what I did wrong! Because of the fillet in the top rail I assumed Revit would do the same for the non continuous rail.
I did not think about it to use a curved segment.
Thanks for that !
Another smaller question .
I understand why Revit is doing this but I don't like it.
Because of the Slope the height of the extended top rail is different.
In this case I would prefer that the extended part of the rail would follow the slope instead of going to horizontal.
Same here, draw as one railing with multiple segements.
Did that (see picture below) but I don't like it a lot.
I prefer two seperate railings but I can live with it.

Then another issue which I don't think is possible (with the clients demands).
Because of the "adaptation" I doubt if I can extend my non continuous rail in this case (should be a joint in the railing because the construction parts are moving differently).

here too, draw as one railing with multiple straight segments and a curve segment turning corner.
Curved segment has been done but there should be a joint in the railing and therefore seperate railings.
Anyway, I think the clients demand to have posts every 900mm is not possible so I switched to "spread pattern to fit" in baluster placement instead of "Center". Like this spacing is max. 900mm instead of fixed 900mm.
It would be nice though to have more control for the placement of the corner posts (set to none for the moment).
Thanks a lot for your help !