The problem was that that support's disk was not rotated according to the railing path.
Added WALL_MOUNTED_HANDRAIL type for railing modifier. It's still a bit work in progress - still need to add support for different railing termination types. Here's the short demonstration - https://user-images.githubusercontent.com/9417531/234582621-6c6f948b-9cdc-4be6-b380-17ddbf5803bf.mp4