Compare zip files containing jars reporting change when nothing is changed

[debraj-manna]

I am using pkgdiff to compare two zip files containing multiple jars. One of the jar is build (dedup-0.001-SNAPSHOT.jar) and rest are downloaded from maven repo and then all are added in zip as part of maven build. pkgdiff is reporting change when there is nothing changed in dedup-0.001-SNAPSHOT.jar

dmanna-m01:es-plugins dmanna$ pkgdiff  ~/Desktop/hbase-co/1/dedup-0.001-SNAPSHOT.zip ~/Desktop/hbase-co/2/dedup-0.001-SNAPSHOT.zip
reading packages ...
comparing packages ...
creating report ...
result: CHANGED (0.000002%)
report: pkgdiff_reports/dedup/0.001-SNAPSHOT_to_0.001-SNAPSHOT/changes_report.html

The detailed report is empty.

dmanna-m01:details dmanna$ pwd
/Users/dmanna/code/github/vnera/main/es-plugins/pkgdiff_reports/dedup/0.001-SNAPSHOT_to_0.001-SNAPSHOT/details
dmanna-m01:details dmanna$ ls
dmanna-m01:details dmanna$

The surprising part is if I unzip and then compare the jar which is reported as different then pkgdiff reports that the there is no change.

dmanna-m01:hbase-co dmanna$ pkgdiff 1/dedup-0.001-SNAPSHOT/dedup-0.001-SNAPSHOT.jar 2/dedup-0.001-SNAPSHOT/dedup-0.001-SNAPSHOT.jar
reading packages ...
comparing packages ...
creating report ...
result: UNCHANGED
report: pkgdiff_reports/dedup/0.001-SNAPSHOT_to_0.001-SNAPSHOT/changes_report.html
dmanna-m01:hbase-co dmanna$

Is this some issue on pkgdiff ? How can I know what exactly is differing in dedup-0.001-SNAPSHOT.jar when it is part of zip file?