Comment 3 for bug 1569583

align=center is deprecated, even in HTML 4, and completely disallowed in HTML 5.
https://www.w3.org/TR/html4/present/graphics.html#h-15.1.2

You really should not be using MS word HTML output, it is awful. Convert
the docx file from word directly instead. ALternately, replace
align=center with style="text-align:center" in the HTML and you will be
fine.

 status invalid