Instance static mesh not part of the navmesh in multiplayer packaged build

I’m trying to chase down a bug where AI characters behave as if a part of level doesn’t exist. They seem to be on a path that goes through a mesh resulting with them perpetually walking into a wall (which that mesh represents).

The meshes in question are the instanced static meshes generated by VASplineSnag. The interesting (and annoying) part is that everything works in the editor. Everything works in the packaged build in singleplayer. However, when I start multiplayer, everything breaks. It’s as though that meshes are not part of the navigation mesh at all.

Has anyone encountered anything similar? Does anyone have any idea how to debug this properly?

perhaps: Project Settings > Navigation System > Allow Client Side Navigation