How do I disable "transitive package management"?

I wish to do so, so that I can install a package that I "packed" locally and have in a .nupkg file. When I attempt to do so, I get a messaging stating that The 'Source' parameter is not respected for the transitive package management based project(s) {csproj file}. The enabled sources in your NuGet configuration will be used.

Complete Context

When developing a NuGet package that's not ready for distribution via our NuGet feed, I often create a local .nupkg file like this from the package manager console:

nuget pack {path-to-csproj-file}

This generates a {project-name}.nupkg file, which I can then install in another project by opening it in Visual Studio, navigating to the package manager console, and entering the command

Install-Package {path-to-nupkg-file}

This has worked great and once the NuGet package is ready for distribution, we push it up to Azure DevOps and let the build pipeline there push it into our feed.

However, I just recently inherited a project where the prior developer apparently setup "transitive package management" that prevents this workflow. Here's what I get when I try to install directly from a .nupkg file:

Install-Package C:\Users\Josh\source\repos\SpeakerDiscountManager\SpeakerDiscountData.1.0.5.nupkg
The 'Source' parameter is not respected for the transitive package management based project(s) MembershipApplicationWidget\MembershipApplicationWidget.csproj. The enabled sources in your NuGet configuration will be used. 
<snipped several lines of unsuccessfully searching configured package sources>
Install-Package : NU1102: Unable to find package SpeakerDiscountData with version (>= 1.0.5)

Obviously, it doesn't find the package I've specified via file, because it is searching online feeds and it doesn't exist in any of our online package sources--the package is in a testing state, not ready for anyone to use but me.

Based on the error message, I need to turn off "transitive package management" so that I can specify a file source for the package, but I've been unable to turn up any information online about how this is configured.

I did try installing this exact same .nupkg file in another project, using the same Install-Package {path-to-nupkg-file} procedure. This works.