AAS before processing with Basyx: it has an empty manufacturer name:

AAS after processing with Basyx: the manufacturer name is gone:

So, basically the difference is between "" (empty string) and None (null).
IMHO, the cause is in line 219 of xml_deserialization.py
Proposed fix:
if element is None:
return None
return element.text if element.text is not None else ""