Hi Jason - I have just started using the docx4j API and find it really useful. Great work!
I am using the MailMerge functionality and found that the Paragraph containing the field is losing any formating it may have had. I found a fix for the FieldsPreprocessor.class that I have included below - please use it if you find it helpful.
Regards,
Paul
public static P canonicalise(P p, List<FieldRef> fieldRefs) {
/*
* Result ...