Comment 2 for bug 1360417

This also happened to me with the oneconf-service:

https://errors.ubuntu.com/oops/f870f968-2975-11e4-8440-fa163e78b027

/etc/apt/sources.list was having read permissions removed from it by apt-clone, a bug which has since been fixed. But again having this issues reported to the Error Tracker would be a good thing.