Differences between PR build and local/official build

We are moving to Central Feed Service so we defined a new feed containing all the packages we consume. The feed contains upstream sources where the actual packages are. Whenever someone who has permission to write to the feed builds the project, feed can update the packages from upstream based on the versions used. So when setting up the feed, I got all the packages we use populated in the feed while building on command line. The same setup also worked for our official pipeline.

But for our PR build pipeline, it started throwing error with missing packages. Most of the packages missing seemed to be related to netstandard.library and dependencies. I couldn't figure out what is referencing it or how it is consumed in official/local build that it doesn't need to download it. For PR build it tries to download from nuget feed. All the missing packages are from Nuget so we were downloading them earlier without actually knowing so behavior hasn't changed.

We should investigate why there are additional packages being downloaded for PR build only.