<h3>Component 1</h3>
@Content
@code {
    [Parameter]
    public RenderFragment? Content { get; set; }
    [Parameter]
    public Func<int, int>? MyFunc { get; set; }
    [Parameter]
    public (int, int)? MyTuple { get; set; }
Which is used into Component2.razor:
<h3>Component 2</h3>
<Component1 Content="ContentNullable"  /* Warning CS8601 */
            MyFunc="MyFuncNullable"    /* Warning CS8601 */
            MyTuple="MyTupleNullable"> /* Ok */
</Component1>
@code {
    public RenderFragment? ContentNullable { get; set; }
    public Func<int, int>? MyFuncNullable { get; set; }
    public (int, int)? MyTupleNullable { get; set; }
And you get the CS8601 warning on Content and MyFunc parameters assignment.
The code generated for Component2.razor includes the following relevant lines:
__builder.AddAttribute(2, "Content", new Microsoft.AspNetCore.Components.RenderFragment(
#nullable restore
            ContentNullable
#nullable disable
__builder.AddAttribute(3, "MyFunc", new System.Func<System.Int32, System.Int32>(
#nullable restore
        MyFuncNullable
#nullable disable
__builder.AddAttribute(4, "MyTuple", Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck<(System.Int32, System.Int32)?>(
#nullable restore
            MyTupleNullable
#nullable disable
Further technical details
ASP.NET Core version: 3.1.300
Include the output of dotnet --info
SDK de .NET Core (reflejando cualquier global.json):
 Version:   3.1.300
 Commit:    b2475c1295
Entorno de tiempo de ejecución:
 OS Name:     Windows
 OS Version:  10.0.18363
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\3.1.300\
Host (useful for support):
  Version: 3.1.4
  Commit:  0c2e69caa6
.NET Core SDKs installed:
  3.1.300 [C:\Program Files\dotnet\sdk]
.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download
          
Thanks for contacting us.

We're moving this issue to the Next sprint planning milestone for future evaluation / consideration. We will evaluate the request when we are planning the work for the next milestone. To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.
          
We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.
  feature-blazor-component-model
  Any feature that affects the component model for Blazor (Parameters, Rendering, Lifecycle, etc)
  labels
      Apr 20, 2021
          
Hi. Thanks for contacting us.

We're closing this issue as there was not much community interest in this ask for quite a while now.

You can learn more about our triage process and how we handle issues by reading our Triage Process writeup.
    feature-blazor-component-model
  Any feature that affects the component model for Blazor (Parameters, Rendering, Lifecycle, etc)
    nullable
    severity-major
  This label is used by an internal tool