RegisteredForRemoteNotifications override not being called, ever

[CMarcher]

Steps to Reproduce

1. On the Apple Developer console, create an app id with Push Notifications enabled, and then edit the Push Notifications section to create a development APNs certificate. Create a provisioning profile with that app id, install on your system or download from the Apple Account sections under Preferences.
2. Add "com.apple.developer.aps-environment" to Entitlements, and set the value to "development".
3. In the AppDelegate, under FinishedLaunching, add this code before base.DidFinishLaunching is called:

var app = NSApplication.SharedApplication;
app.RegisterForRemoteNotifications();
app.RegisterForRemoteNotificationTypes(NSRemoteNotificationType.Badge);

4. Add an override for RegisteredForRemoteNotifications in the AppDelegate. Add something like Debug.WriteLine("This function has been called."); inside. Add a breakpoint if you'd like.
5. Run the app.

Expected Behavior

RegisteredForRemoteNotifications override is called.

Actual Behavior

RegisteredForRemoteNotifications is not called, therefore I cannot set up the notification server.

Environment

=== Visual Studio Community 2019 for Mac ===

Version 8.8.10 (build 2)
Installation UUID: d7bdbec6-b34c-4d80-ba0e-0be0e59dff33
	GTK+ 2.24.23 (Raleigh theme)
	Xamarin.Mac 6.18.0.23 (d16-6 / 088c73638)

	Package version: 612000122

=== Mono Framework MDK ===

Runtime:
	Mono 6.12.0.122 (2020-02/c621c35ffa0) (64-bit)
	Package version: 612000122

=== Roslyn (Language Service) ===

3.8.0-5.20519.18+4c195c3ac1974edcefa76774d7a59a2350ec55fa

=== NuGet ===

Version: 5.8.0.6860

=== .NET Core SDK ===

SDK: /usr/local/share/dotnet/sdk/5.0.103/Sdks
SDK Versions:
	5.0.103
	3.1.406
MSBuild SDKs: /Applications/Visual Studio.app/Contents/Resources/lib/monodevelop/bin/MSBuild/Current/bin/Sdks

=== .NET Core Runtime ===

Runtime: /usr/local/share/dotnet/dotnet
Runtime Versions:
	5.0.3
	3.1.12

=== .NET Core 3.1 SDK ===

SDK: 3.1.406

=== Xamarin.Profiler ===

Version: 1.6.15.68
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler

=== Updater ===

Version: 11

=== Xamarin.Android ===

Version: 11.1.0.26 (Visual Studio Community)
Commit: xamarin-android/d16-8/a36ce73
Android SDK: /Users/calebarcher/Library/Developer/Xamarin/android-sdk-macosx
	Supported Android versions:
		None installed

SDK Tools Version: 26.1.1
SDK Platform Tools Version: 30.0.4
SDK Build Tools Version: 29.0.2

Build Information: 
Mono: 5e9cb6d
Java.Interop: xamarin/java.interop/d16-8@79d9533
ProGuard: Guardsquare/proguard/proguard6.2.2@ebe9000
SQLite: xamarin/sqlite/3.32.1@1a3276b
Xamarin.Android Tools: xamarin/xamarin-android-tools/d16-8@2fb1cbc

=== Microsoft OpenJDK for Mobile ===

Java SDK: /Users/calebarcher/Library/Developer/Xamarin/jdk/microsoft_dist_openjdk_1.8.0.25
1.8.0-25
Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL

=== Android SDK Manager ===

Version: 16.8.0.32
Hash: 01a7774
Branch: remotes/origin/d16-8
Build date: 2021-01-14 00:34:58 UTC

=== Android Device Manager ===

Version: 16.8.0.46
Hash: 0a81419
Branch: remotes/origin/d16-8
Build date: 2021-01-14 00:35:22 UTC

=== Apple Developer Tools ===

Xcode 12.4 (17801)
Build 12D4e

=== Xamarin.Mac ===

Version: 7.4.0.10 (Visual Studio Community)
Hash: a4c70e7d0
Branch: xcode12.4
Build date: 2021-02-17 17:40:51-0500

=== Xamarin.iOS ===

Version: 14.10.0.4 (Visual Studio Community)
Hash: 5a05865f6
Branch: xcode12.4
Build date: 2021-01-28 02:30:23-0500

=== Xamarin Designer ===

Version: 16.8.0.510
Hash: 44e3f3ce9
Branch: remotes/origin/d16-8
Build date: 2020-12-10 00:06:14 UTC

=== Build Information ===

Release ID: 808100002
Git revision: f81ffa2444a28c09f173849935ec9ee0195a5b17
Build date: 2021-02-18 12:02:12-05
Build branch: release-8.8
Xamarin extensions: f81ffa2444a28c09f173849935ec9ee0195a5b17

=== Operating System ===

Mac OS X 10.16.0 (not a part of the log, but my actual version number is 11.2.1)
Darwin 20.3.0 Darwin Kernel Version 20.3.0
    Thu Jan 21 00:07:06 PST 2021
    root:xnu-7195.81.3~1/RELEASE_X86_64 x86_64

[CMarcher]

I'm currently on Big Sur, and I found this.

It seems notifications work pre-Big Sur for development environments, but with Big Sur this is no longer true. Production is supposedly unaffected.

[CMarcher]

After changing the environment to production and signing with a production provisioning profile, I can confirm that Big Sur is the issue, as the override is being reached now. This is an Apple issue, not something that can be fixed here.