Convex Collision Degeneration when importing from Blender to UE4

Hello everyone.
I’m trying to import a mesh created in Blender into UE4 project. The mesh is going to be used in as race track spline mesh segment, so I need a detailed sub-divided collision for it, because I need to accurately represent collision when the mesh is deformed in any way.

The model I’ve created looks like this:
http://prntscr.com/tgwi17
It’s nothing special - a simple sub-divided cube, scaled for specific segment size.
When I import it into project, I get a degenerated collision - all the geometry is collapsed into 1 box:
http://prntscr.com/tgwjmt
Please note that the complex collision looks fine:
http://prntscr.com/tgwkg3

The question is: what do I need to use in order to make a simple custom collision imported from Blender to look exactly as it’s created?
I’d like to avoid using “Complex as Simple” - or rather, up till now I’ve been using it, but I find it to still have many issues, aside from the obvious performance penalty when used massively.

If any additional information is required, please let me know.
And thanks in advance for all the ideas and heads-ups.

Forgot to mention, the issue is present in every UE4 version, starting from at least 4.13 (and maybe even older ones).