javadoc will add timestamps to the HTML file it produces.
strip-nondeterminism will normalize files generated by Javadoc.
There's a problem with packages that use maven-repo-helper: its mh_install script is sequenced after dh_stripnondeterminsim. So the documentation of these packages is not processed.
From man javadoc:
-notimestamp Suppresses the timestamp, which is hidden in an HTML comment in the gener‐ ated HTML near the top of each page. Useful when you want to run javadoc on two source bases and diff them, as it prevents timestamps from causing a diff (which would otherwise be a diff on every page). The timestamp includes the javadoc version number, and currently looks like this: <!-- Generated by javadoc (build 1.5.0_01) on Thu Apr 02 14:04:52 IST 2009 -->
A wishlist bug (783938) has been filed to change the default behavior of javadoc to not include timestamps.