"Last downloaded" not updating consistently in NuGet

With nuget hosted repositories, the command "nuget install" updates the "Last downloaded" attribute of an asset as it should.

However, when you use "dotnet restore" or "dotnet add package", the asset's "Last downloaded" attributes are not updated.
As we use "Last downloaded" attribute to determine if assets that are no longer used can be cleaned, this messes with our cleaning. I have currently disabled the cleaning therefore for the nuget hosted repositories.

I've tested with:

• NuGet Version: 5.6.0.6489 -> works ok: last downloaded is updated
• dotnet --version: 2.2.207 -> works not ok: last downloaded is not updated
• dotnet --version: 3.1.201 -> works not ok: last downloaded is not updated

Examples:

• Ok (last downloaded is updated):

   $ nuget install -Version 1.0.0 myfirstpackage
  

• Not ok (last downloaded is not updated):

  $ dotnet add package -v 1.0.0 mysecondpackage
  

I've used the same NuGet.Config to define the nuget repositories in nexus3.