I have noticed that many railclone objects, especially Metal Fences behave strange on curves.
For example in the image attached, you can see that the posts are fine, but the top rail is detached.
I solved it by adding more vertexes to the spline, but its just a workaround and they are still separated.
I use AutoCAD architecture 2014. Sometimes railclone does have a weird behavior with ACA objects and splines.
But I don't see how is it connected.