Nav octree memory is not correctly reporting memory usage.

STAT_Navigation_CollisionTreeMemory and STAT_NavigationMemory are not accounting for DEC_MEMORY_STAT_BY OctreeSizeBytes in the navoctree destructor. It appears STAT_Navigation_CollisionTreeMemory ElementMemory is also not being decremented.

There are other potential code paths that do not seem to be accounted for too like FNavigationOctreeController::Reset().

Create a single player level with some geometry and a dynamic navmesh.
Play the level and display navigation memory stats
Issue RestartLevel Console Command.
Note nav octree stats grow each time the level is restarted.