[4.14] Spline Mesh Collision Issue

Hiya

I am getting a consistent error with spline mesh collision in 4-14 (all preview releases)

I have some very long splines with custom collision,

Please see post

post 212 page 6

If I draw a short spline the collision looks ok , over 100m? and the results corrupted as shown.

This has been repeated in multiple projects and versions.
All 4,14 are corrupted.
Any other release all is ok

Regards

Paul G