My TeamCity server has two build configurations that build .nupkg packages on a nightly basis. One build configuration's artifacts seem to be added to the TeamCity nuget public feed reliably, while the other build configuration apparently hasn't published anything in over a month.
Note that neither build configuration actually uses the nupack build steps in teamcity. They use MSBuild steps within which .nupkg files are created and the build configuration recognizes are build artifacts. Both build configurations are the same in this respect.
The build configuration whose recent artifacts do not show up in the feed: http://teamcity.dotnetopenauth.net:82/viewType.html?tab=buildTypeStatusDiv&buildTypeId=bt3
The build configuration whose artifacts do show up in the feed: http://teamcity.dotnetopenauth.net:82/viewType.html?buildTypeId=bt63&tab=buildTypeStatusDiv
The feed: http://teamcity.dotnetopenauth.net:82/guestAuth/app/nuget/v1/FeedService.svc
The Nuget packager command, when targeting this NuGet feed:
PM> Get-Package -Pre -ListAvailable -AllVersions
I see all the daily packages from the working build configuration and the ones from the non-working build configuration has just a few (old) entries.