Serious problems and questions when building ASP.NET Core from sources

[AlexeiSosnov]

Description:
I am attempting to build ASP.NET Core 8.0.12 from source on Linux (Ubuntu 22.04) using the standard instructions. My build command is:
eng/build.sh --restore --pack --build-managed --build-native --no-build-java --no-build-installers --configuration Release --arch x64 --build --no-test --no-build-nodejs

Issues encountered:

1. Missing Microsoft.AspNetCore.Mvc.NewtonsoftJson.nupkg in artifacts
   Despite including the --pack option, the Microsoft.AspNetCore.Mvc.NewtonsoftJson.nupkg package does not appear in artifacts/packages/Shipping.
   The only observable difference is that this package does not have <IsShipping>true</IsShipping> in its .csproj file.
   Manually adding true leads to inconsistent results: the package is occasionally generated, but not reliably.

2. Workstation crashes during build
   The build reproducibly crashes the workstation at the "Finished crossgen..." stage.
   System specs: 32 GB RAM, 1 TB SSD (should be sufficient for large builds).

Questions:

1. Missing package:
   How can Microsoft.AspNetCore.Mvc.NewtonsoftJson.nupkg be reliably generated in the build artifacts?
   If this package is not marked as "shippable," how does it end up in the official NuGet repository? Does IsShipping have no impact on the build output?

2. Workstation crashes:
   What could cause a reproducible system crash during the crossgen stage? Are there known memory/CPU constraints or diagnostics to investigate this?

Any guidance on troubleshooting or adjustments to the build command would be appreciated.

More details:
The workstation crashes on crossgen step:
"$HOME/.nuget/packages/microsoft.netcore.app.crossgen2.linux-x64/8.0.12/tools/crossgen2" $HOME/aspnetcore-from-sources/artifacts/obj/Composite/Release//full-composite.r2r.rsp