It also happens at a new install of Ubuntu 20.04. Today it just happened again with the software in the attachment: these are the updates are found on synaptic that didn't showed up on snap-store or update-manager.
** Attachment added: "20200520.png" https://bugs.launchpad.net/snap-store/+bug/1878931/+attachment/5374702/+files/20200520.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1878931 Title: ubuntu-software does not update apt software To manage notifications about this bug go to: https://bugs.launchpad.net/snap-store/+bug/1878931/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs