Hey there,
If you open a Document that has a dependency to a private nuget (not hosted on nuget.org) that you don’t have installed yet, trying to install it from the Document menu (clicking “Exact Referenced Version” for instance) won’t work. It says the nuget cannot be found.
But if you install it “manually” from the Quad menu right after, it works.
It looks like installing a nuget from the Document menu only looks for public sources.