We are testing railclone 4 (same issue with 4.0.9 and 4.1.0) with Vray and VrayProxies and I noticed 2 major problems.
1- The renderer becomes very unstable (crashes often) when "use segment material" is activated
2- Unproper rotation of objects (viewport & render are diferent) ; see attached image
This happens only while the car is a vrayProxy, it's solved as soon as the proxy is converted to poly. A transform node after the segment does the right operation though.
Vray version is VrayNext update2 (build 4.20), 3ds max is 2020.
The exact same operation has been tested with railclone 3.31 with no issue.
For the moment we won't upgrade to 4.