i don't think there is a bug since i can easily read the data from the dictionary.
I don't have a example at hand (since they are all way to big)
But this is what is added to each entity :
e.set_attribute 'libraryname', 'suid', variable (number)
e.set_attribute 'libraryname', 'mat_or', name of the original material (text)
when a face;
e.set_attribute 'libraryname', 'matback_or', name of the original material (text)
e.set_attribute 'libraryname', 'typestatus', name of a material (text)