Bot Framework Emulator locale problem for pt-BR

Question

I'm facing a problem with bot framework emulator when I try to use Microsoft Virtual Assistant sample in Brazilian Portuguese(pt-BR). In the microsoft sample we have the following method in the BotService.cs class

public CognitiveModelSet GetCognitiveModels()
    {
        // Get cognitive models for locale
        var locale = CultureInfo.CurrentUICulture.Name.ToLower();


        var cognitiveModel = CognitiveModelSets.ContainsKey(locale)
        ? CognitiveModelSets[locale]
        : CognitiveModelSets.Where(key => key.Key.StartsWith(locale.Substring(0, 2))).FirstOrDefault().Value
        ?? throw new Exception($"There's no matching locale for '{locale}' or its root language '{locale.Substring(0, 2)}'. " +
                                "Please review your available locales in your cognitivemodels.json file.");

        return cognitiveModel;
    }

However, when try to run the program the following error happens:

    fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[1]
      An unhandled exception has occurred while executing the request.
System.ArgumentOutOfRangeException: Index and length must refer to a location within the string. (Parameter 'length')
   at System.String.Substring(Int32 startIndex, Int32 length)
   at YestFotoPropostaBot.Services.BotServices.<>c__DisplayClass6_0.<GetCognitiveModels>b__0(KeyValuePair`2 key) in /Users/igorazevedo/Documents/Estagio/YestFotoPropostaBot/YestFotoPropostaBot/YestFotoPropostaBot/Services/BotServices.cs:line 77
   at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
   at System.Linq.Enumerable.TryGetFirst[TSource](IEnumerable`1 source, Boolean& found)
   at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)
   at YestFotoPropostaBot.Services.BotServices.GetCognitiveModels() in /Users/igorazevedo/Documents/Estagio/YestFotoPropostaBot/YestFotoPropostaBot/YestFotoPropostaBot/Services/BotServices.cs:line 75
   at YestFotoPropostaBot.Dialogs.MainDialog..ctor(IServiceProvider serviceProvider, IBotTelemetryClient telemetryClient) in /Users/igorazevedo/Documents/Estagio/YestFotoPropostaBot/YestFotoPropostaBot/YestFotoPropostaBot/Dialogs/MainDialog.cs:line 80
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitDisposeCache(ServiceCallSite transientCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)
   at lambda_method(Closure , IServiceProvider , Object[] )
   at Microsoft.AspNetCore.Mvc.Controllers.ControllerActivatorProvider.<>c__DisplayClass4_0.<CreateActivator>b__0(ControllerContext controllerContext)
   at Microsoft.AspNetCore.Mvc.Controllers.ControllerFactoryProvider.<>c__DisplayClass5_0.<CreateControllerFactory>g__CreateController|0(ControllerContext controllerContext)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

In other words, the main error is

System.ArgumentOutOfRangeException: Index and length must refer to a location within the string. (Parameter 'length')
   at System.String.Substring(Int32 startIndex, Int32 length)

Apparently the variable "locale" is null, and for this reason the error is happening. Therefore, I believe the error is not in the code but in Mac bot framework emulator since in the Windows bot framework emulator this same code is working perfectly.

As it is possible to see in the link(image) below, I have configured my locale variable in bot framework emulator to be "pt-BR". Nonetheless, this is not the root cause of the error, but something else I not being able to identify.

bot emulator framework configuration page