Hello,
We have run the script with phpdocx 5.5 and the output isn't the same than yours. We think you are using RTL options (the alignments of the cells aren't the default), Tidy for PHP is not installed, you have enabled the strictWordStyles option when importing the HTML (this option disable adding some styles from the HTML) or the source code of library has been changed.
Please run the script using a fresh installation of phpdocx. We also have sent to your e-mail the DOCX output of this script on our test servers, as you can check with MS Word and LibreOffice, both alignments are correct.
Regards.