When you start NavMeshing your cell area, is it imperative that it be PERFECTLY lined up to the wall? Because I'm finding this to be SO difficult to do lmao.
I mean I can get it close, but lining it up right to it is friggen hard.

Will this cause an issue if an npc somehow gets pushes or gets into the 1cm area between the navmesh and the wall?

It shouldn't cause any problems. After all, NPCs are somewhat larger than 1cm, so most of their body will still be in the navmeshed area.

And the AI will force the creatures or NPC's back onto the nav-mesh. They do not travel in un-nav-meshed areas.

I actually find it better to keep my nav-meshes away from the walls so they don't get stuck or clip into the walls.

Ok, nice thanks alot.

I just make sure that my navmesh is very close to the point of the wall that sticks out most. That way they never clip (like Willie said) but can still walk near them if neccisary. So long as when you say detect cover edges, it knows theres a wall there your close enough.