Commented Unassigned: Manage nuget for solution does not correctly show the new packages [3373]

I have notice that when we work in a team if one of my colleague update the package on his side and publish the changes to our vcs, then if I downlload this update the visual studio manager will keep offering me to update the same packages again and again. I have notice that if I remove the old package from my disk(packages directory) then the Package manager stop offering. It seems that the list of possible update is link to what I have on disk and not what are my real dependencies.
Comments: The version we are using is 2.6.40627.9000 (01July2013) I have checked with one of my colleague that has a many months old package directory(that contains many versions of the same libraries). When he opens the "Manage Nuget for Solution" window he is offered to update 3 pages of packages ( he should only have one or two packages to update instead). If he tries to update a package he the window that describes which project are about to be updated , there are none ( few projects are greyed but they already contains the up to date version, so no update will occured). So it does mean that no projects are referencing anymore this old package but the package manager keep offering me to update them. Then when delete the package directory and reopen the "Manage Nuget for Solution" window he is now offered only the few packages that we do need to update.