I was bitten by navmesh merging in 3D, say you have several loaded scenes, each with a navmesh. If the navmesh points are matching up to an undocumented degree,

I was bitten by navmesh merging in 3D, say you have several loaded scenes, each with a navmesh. If the navmesh points are matching up to an undocumented degree, the navmeshes will be merged. This is dependent upon the scene own Transform, as floating point will yield slightly different float results depending on how the navmesh point are transformed to world space. I ended up generating navmesh from an apriori description instead of Godot scenes. "optimized" path-finding into these navmesh was surprisingly poor too (considering a lot of the rest is great). The problem is that none of the problems are documented.