Comment 6 for bug 1731762

My suspicion is that the jigdo file is a snapshot of the .deb files that appear on the iso and that because this is a point a release the jigdo file points to .deb files which used to exist in -updates or -security that have been superseded by newer versions. If that's correct a .jigdo file for point releases (16.04.3) is only useful for a very short period of time.