I have been doing some troubleshooting to figure out why portal.nlm is not
getting updated when SP4 is installed. It appears to only happen on servers
where the post-sp3 portal.nlm (nw65os3a or nw65os3b) has been applied.
Putting the original portal.nlm from sp3 back in place before applying the
service pack appears to work fine.

Can anyone else confirm this in their environment?