Spent about 2 weeks now trying to get a very simple A-B Spline mesh work where the mesh stretches between two moving points (like a tether), but I’ve noticed that the Spline Mesh’s collision really doesn’t consistently work.
I can actually place a spline down in the editor (with collisions view enabled), move the end position down, and see that the initial collision box for the mesh doesn’t scale whatsoever. If I tick AllowCPUAccess on and off in the material used, and save it, the collision works fine. But upon moving the Spline in the editor and trying again, the collision is gone again.
Been looking around for answers to this for a while now, but seems like there are none 
please help!
Example: UE4 Spline Issue - YouTube