Hello,
UPDATE: the current stable release of customizeWordContent allows replacing all font attributes.
The current version of customizeWordContent replaces w:ascii, w:hAnsi and w:cs attributes, and the current beta branch also replaces w:eastAsia, this may be the problem. Please send the DOCX to contact[at]phpdocx.com so we can check it. Also please send us if you are using the classic or namespaces package and we'll send you the updated class, it's a minor change.
Regards.