When importing fbx, sometimes happen, that even if texture and material exists, importer makes new material in typical convention objectname-materialname instead of using existing one. Material generation settings are OK. It only does for some meshes. I tried to compare these problematic meshes with meshes which are working correctly (using same materials both) in my 3d modelling app, but I was not able to find difference.
Sometimes, when material is not existing, instead of making new material named as texture, it makes material named objectname-materialname. It sometimes helps to delete “objectname-” from material name and reimport and everything is OK. WTF?
Can it be some bug in fbx importer? When importing as obj, it almost always makes new material. I am not sure, that this is correct behaviour for “per texture” import settings.