Separate surfaces cover each other in navmesh

Hello and thank you, Unity, for these Navigation updates.

I have two areas where my agents run about. One is the normal floor where people move. Another is a table where little creatures move.

I have placed a mesh surface script on my terrain (where people move), set it to my people agent type and voila. Looks great (except for another issue which I will raise in a separate post).

I then place a mesh surface script on my table, set it to my creature agent type and hit bake. The terrain that people are running around on has now also been given a navmesh for my creatures - which I do not want it to do and I do not believe this is expected.

I believe your design pattern was that one surface would have multiple surface scripts, one for each agent type desired, to produce its own navmesh each. However the script does not seem to limit itself to its object and children. Both of these objects are in my game root and otherwise not related.

I have tried placing a 2nd surface mesh script on my terrain (for people) and set it to creatures with the default area as non-walkable. However this doesn't work.

This isn't a game breaker for me, as the creatures cannot escape to the floor without an off-mesh link which I haven't provided, however this is probably an easy fix before release.

Thank you!