Hi, as You have found- setting to higher "Curve Steps" value is one way to do it. Most of the times it works really well.
Anyway that does not work sometimes with some conditions,- ie high poly objects and curvy splines, as it in Your case.
What is more, deformed segments are not instanced- each deformed segment requires it's own RAM allocation,- so be careful..
So it is not recommended way to use High Poly assets with bending in RC.
The most elegant way in this case is to use "lighter" segments and use baked normal maps to bring out the details instead of displaced geometry.
Also I think
this FAQ is related and can help in same cases as well.
Hope this helps.