Comment 10 for bug 454941

Thanks for the replies.

update-manager checks for the last update time via the file:

/var/lib/apt/periodic/update-success-stamp

That is written every time a apt-get update/aptitude update/update-manager check update *without* any errors was done. A error can be e.g. unreachable third party repository, no network connectivity etc. If you see incorrect information like above, please check the timestamp of that file and check if apt-get update (on a terminal) runs without errors or warnings. If both is the case, then there is a bug.