Dang, I thought I had managed to find and fix all the objects with inverted normals. Oh well, I'll fix it at some point, let's first see if any other issues crop up.
Sounds like a simple case of inverted normals on those polygons. Takes about 2 seconds to fix
Easy for you modellers to say.
Sure, applying the fix to my working file takes 2 seconds, but after that the re-conversion through PCS2 takes a few minutes, then generating a new cache file takes about 5 minutes, and committing cache and model files (~30mb) takes another 5 minutes. Anyway, as I said I'll wait and see if anything else needs fixing or adding so that I don't need to do that several times.