Missing packages when migrating from 3.7 to 3.8

Hi there,
I try to upgrade my solution (with many projects) from 3.7 to 3.8. Every projects was updated to the new file format but it seems that the MonoGame dll is missing when I try to compile the sources.

Here is a library project

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
    <PackageReference Include="Jitter.Standard" Version="1.0.0" />
    <PackageReference Include="MonoGame.Framework.WindowsDX" Version="">

And a game project

WinExe netcoreapp3.1 false false true app.manifest Icon.ico Content\Content.mgcb Content\Shaders.mgcb

And the result when I try to build

Thanks for the help!