Cat it after the sed, not before.

templates/packagebuild.xml

@@ -45,8 +45,8 @@ mv -v debian {{ NAME }};
 git clone {{ UPSTREAM_URL }} upstream;
 export VERSION="$(head -1 {{ NAME }}/debian/changelog | sed -n '/(/,/)/{:a; $!N; /)/!{$!ba}; s/.*(\([^)]*\)).*/\1/p}' | cut -d '-' -f1)+git$(date +'%Y%m%d%H%M')";
 export CHANGELOG_ENTRY="{{ NAME }} ($VERSION-0ubuntu1~ppa1) {{ RELEASE }}; urgency=low\n\n  * CI upload.\n\n –– Lugito <info@lubuntu.me>  $(date +'%a, %d %b %Y %T %z')\n"
-cat {{ NAME }}/debian/changelog | pastebinit;
 sed -i "1i$CHANGELOG_ENTRY" {{ NAME }}/debian/changelog;
+cat {{ NAME }}/debian/changelog | pastebinit;
 tar cvf {{ NAME }}_$VERSION.orig.tar upstream;
 gzip {{ NAME }}_$VERSION.orig.tar;
 (cd {{ NAME }}; debuild -S -d -sa -k234778F3D70C2B9785EB7426E7BE29862BE6F574; cat ../{{ NAME }}_$VERSION-0ubuntu1~ppa1_source.changes | pastebinit)