Should a line trace hit the back face of a BSP section

I am using a line trace to orient an actor being placed on a surface.

When this is a static mesh, everything works as expected. When it is a BSP section, sometimes it hits the back of the BSP (i.e. from inside the BSP) and orients itself backwards and inside the BSP.

There also doesn’t seem to be any obvious way of working out if it has hit a back face from within blueprint.