Weird exceptions when running a .NET DLL from NI TestStand, but in VS2019 it works smoothly

Question

I'm trying to run my app which includes some SignalR connections and other async methods.

As soon as the codes reaches

connection.StartAsync();

I get this Error:

System.TypeInitializationException: 'The type initializer for 'Microsoft.AspNetCore.Http.Connections.Client.Internal.Constants' threw an exception.'

Inner Exception: FormatException: The format of value '@BuiltBy: dlab-DDVSOWINAGE059 @Branch: release/2.1 @SrcCode: https://github.com/dotnet/corefx/tree/30ab651fcb4354552bd4891619a0bdd81e0ebdbf' is invalid.

This exception was originally thrown at this call stack: System.Net.Http.Headers.ProductInfoHeaderValue.Parse(string) Microsoft.AspNetCore.Http.Connections.Client.Internal.Constants.Constants()

When running from VS all looks good and works fine.

So far, I have no clue.

Any ideas?