With dotnet 5.0 we have seen a new stack overflow introduced in the F# compiler when running on the coreclr.

Repro:
unzip StackOverflow.zip
to your local zip.

The project assumes that a dotnet sdk with net5.0 is installed in c:\program files\dotnet

build this project and run it

dotnet build -t:Rebuild -c release
dotnet run -c release

observe the stack overflow.

If the project file is edited to netcoreapp3.1 and a netcoreapp3.1 runtime is installed, then executing the program will succeed without a stack overflow.