Hi Jacobo, I'm glad you found out what the issue was! Hopefully it is a bug because LWO vertex normals are already complex enough as it is.

Modo was the first program that used vertex normals out of LWO format but unfortunately they decided to use them in the opposite convention of the rest of the coordinates (something like vertex position coordinates in left hand coordinates and vertex normals in right hand coordinates).

Then later on LightWave 9.6 also supported reading vertex normals out of LWO but they expect a different orientation than Modo. Then for some unknown reason they decided to change it to some other direction in LightWave v 10.

Hopefully Modo is not going to now throw in a 4th different possible orientation for the normals, since the current situation of having 3 different possible orientations to use is confusing enough as it is.

- Michael