We get the same error message when deserialiszing:
var data = JsonSerializer.Deserialize<Dictionary<string, dynamic>>(json);
The error is reproducible with Visual Studio 2019 for Mac version 8.9 but not with version 8.8.6. This affects only iOS. More specifically it is the Xamarin.iOS version 14.14.2.5 that has the bug. If you downgrade manually to the Xamarin.iOS version 14.8.0.3 everything is fine again. Deserializing works on Android with both versions of Visual Studio.
Version 8.9:
=== Visual Studio Community 2019 for Mac ===
Version 8.9 (build 1651)
Installation UUID: 00f5a6c3-e367-494e-ac05-f885ac415e0c
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) ===
3.9.0-5.21112.8+f3ff04378c972d435826e6181de364b3c0db8d14
=== NuGet ===
Version: 5.8.0.6860
=== .NET Core SDK ===
SDK: /usr/local/share/dotnet/sdk/5.0.103/Sdks
SDK Versions:
5.0.103
5.0.102
5.0.101
5.0.100
3.1.406
3.1.405
3.1.404
3.1.403
3.1.402
3.1.401
3.1.302
3.1.301
3.1.300
3.1.200
3.1.102
3.1.101
3.1.100
3.0.101
3.0.100
2.1.701
2.1.700
2.1.505
2.1.504
2.1.503
2.1.302
2.1.301
2.1.4
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
5.0.2
5.0.1
5.0.0
3.1.12
3.1.11
3.1.10
3.1.9
3.1.8
3.1.7
3.1.6
3.1.5
3.1.4
3.1.2
3.1.1
3.1.0
3.0.1
3.0.0
2.1.23
2.1.22
2.1.21
2.1.20
2.1.19
2.1.18
2.1.16
2.1.15
2.1.14
2.1.13
2.1.12
2.1.11
2.1.9
2.1.8
2.1.7
2.1.2
2.1.1
2.0.5
=== .NET Core 3.1 SDK ===
SDK: 3.1.406
=== Xamarin.Profiler ===
Version: 1.6.12.26
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler
=== Updater ===
Version: 11
=== Xamarin Designer ===
Version: 16.9.0.316
Hash: bd2705417
Branch: remotes/origin/d16-9
Build date: 2021-02-24 00:16:08 UTC
=== Xamarin.Android ===
Version: 11.2.0.0 (Visual Studio Community)
Commit: xamarin-android/d16-9/f908d16
Android SDK: /Users/marcoseraphin/Library/Developer/Xamarin/android-sdk-macosx
Supported Android versions:
6.0 (API level 23)
7.1 (API level 25)
8.0 (API level 26)
8.1 (API level 27)
SDK Tools Version: 26.1.1
SDK Platform Tools Version: 31.0.0
SDK Build Tools Version: 29.0.2
Build Information:
Mono: 5e9cb6d
Java.Interop: xamarin/java.interop/d16-9@1d382be
ProGuard: Guardsquare/proguard/v7.0.1@912d149
SQLite: xamarin/sqlite/3.32.2@cfe06e0
Xamarin.Android Tools: xamarin/xamarin-android-tools/main@ad80a42
=== Microsoft OpenJDK for Mobile ===
Java SDK: /Users/marcoseraphin/Library/Developer/Xamarin/jdk/microsoft_dist_openjdk_8.0.25
1.8.0-25
Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL
=== Android SDK Manager ===
Version: 16.9.0.22
Hash: a391de2
Branch: remotes/origin/d16-9
Build date: 2021-02-18 03:14:56 UTC
=== Android Device Manager ===
Version: 16.9.0.17
Hash: fc2b3db
Branch: remotes/origin/d16-9
Build date: 2021-02-18 03:15:18 UTC
=== Apple Developer Tools ===
Xcode 12.4 (17801)
Build 12D4e
=== Xamarin.Mac ===
Version: 7.8.2.5 (Visual Studio Community)
Hash: 3836759d4
Branch: d16-9
Build date: 2021-02-10 17:56:43-0500
=== Xamarin.iOS ===
Version: 14.14.2.5 (Visual Studio Community)
Hash: 3836759d4
Branch: d16-9
Build date: 2021-02-10 17:56:44-0500
=== Build Information ===
Release ID: 809001651
Git revision: c05b1dec4362b5956d47624a437e900ffdc9aa0a
Build date: 2021-02-25 11:27:51-05
Build branch: release-8.9
Xamarin extensions: c05b1dec4362b5956d47624a437e900ffdc9aa0a
=== Operating System ===
Mac OS X 10.15.7
Darwin 19.6.0 Darwin Kernel Version 19.6.0
Thu Oct 29 22:56:45 PDT 2020
root:xnu-6153.141.2.2~1/RELEASE_X86_64 x86_64
=== Enabled user installed extensions ===
LiveXAML 1.3.51
Stack Overflow Search 0.7.1
Version 8.8.6
=== Visual Studio Community 2019 for Mac ===
Version 8.8.6 (build 15)
Installation UUID: 41394e34-af16-4443-a055-e3a05dff10ef
GTK+ 2.24.23 (Raleigh theme)
Xamarin.Mac 6.18.0.23 (d16-6 / 088c73638)
Package version: 612000113
=== Mono Framework MDK ===
Runtime:
Mono 6.12.0.113 (2020-02/4fdfb5b1fd5) (64-bit)
Package version: 612000113
=== 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/5.0.102/Sdks
SDK Versions:
5.0.102
3.1.201
2.1.802
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:
5.0.2
3.1.8
3.1.3
2.1.23
2.1.22
2.1.13
=== .NET Core 3.1 SDK ===
SDK: 3.1.201
=== Xamarin.Profiler ===
Version: 1.6.12.29
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler
=== Updater ===
Version: 11
=== Apple Developer Tools ===
Xcode 12.3 (17715)
Build 12C33
=== Xamarin.Mac ===
Version: 7.2.0.3 (Visual Studio Community)
Hash: c51fabee8
Branch: xcode12.3
Build date: 2020-12-10 21:05:04-0500
=== Xamarin.iOS ===
Version: 14.8.0.3 (Visual Studio Community)
Hash: c51fabee8
Branch: xcode12.3
Build date: 2020-12-10 21:05:05-0500
=== Xamarin.Android ===
Version: 11.1.0.26 (Visual Studio Community)
Commit: xamarin-android/d16-8/a36ce73
Android SDK: /Users/Shared/Development/Android/sdk
Supported Android versions:
8.0 (API level 26)
8.1 (API level 27)
SDK Tools Version: 26.1.1
SDK Platform Tools Version: 29.0.4
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/Shared/Development/jdk/microsoft_dist_openjdk_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
=== 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: 808060015
Git revision: d34d29b4643a130479d762e4d2b5750e6462fde7
Build date: 2021-01-15 08:35:04-05
Build branch: release-8.8
Xamarin extensions: d34d29b4643a130479d762e4d2b5750e6462fde7
=== Operating System ===
Mac OS X 10.15.7
Darwin 19.6.0 Darwin Kernel Version 19.6.0
Mon Aug 31 22:12:52 PDT 2020
root:xnu-6153.141.2~1/RELEASE_X86_64 x86_64
=== Enabled user installed extensions ===
DeepClean 1.2.5