navmesh workshop objects disappears

[Sebo85]

I've got a bunch of vanilla meshes to be craftable in workshop. Everything's fine and working except this horrible navmesh!

I've tried the automatic navmesh generation, automatic with manual correction and completely manual, which is a nightmare when it comes to edges of floors :D

 

So effectively I've got this to work BUT sometimes when I finalize a navmesh, all those pretty triangles disappear and I don't know if it is finalized or not cause when I reenter the objects navmesh, there's no navmesh at all!

 

The mesh itself is completely vanilla, didn't touch the collision or anything else, just added snappoints.

 

 

Thanks in advance guys and gals