This is because you installed from a point release, which uses xenial- updates, and then you disabled xenial-updates in your sources.list. That's not a supported or supportable configuration, and certainly not a dpkg bug.
** Changed in: dpkg (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1727819 Title: Depends: libdpkg-perl (= 1.18.4ubuntu1) but 1.18.4ubuntu1.2 is to be installed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dpkg/+bug/1727819/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs