Hello,
We have run the same code with phpdocx 5.5 and the output is correct as well.
What program and version are you using to open the DOCX? We have opened it with MS Word 2007, MS Word 2010, MS Word 2013, MS Word 2016, LibreOffice 5 and LibreOffice 6 and all show the correct alignments.
You can send the DOCX output you get to contact[at]phpdocx.com
Regards.