Hello,
How have you generate the table style? We have done some quick tests and using createTableStyle it works perfectly with all DOCX readers; maybe you have generated or added the style in a way that is only compatible with MS Word 2019? We have test also adding custom paragraph styles to the HTML and this approach works fine as well.
Please test and run the included examples. We also recommend you to open a support ticket (https://www.phpdocx.com/support), and the dev team well check your DOCX and script to find any issues.
Regards.