Get "client info is null" with MSAL 1.1.0-preview - msal

Question

I have some code that was working on MSAL 1.1.0-alpha307, but on 1.1.0-preview it throws exception "client info is null", which is returned in the HTTP response. The app is registered in the AAD V2 endpoint and it gets MS Graph data. From the stack trace below, it looks like its able to get the token for Graph but not able to cache it.
Can anyone suggest a diagnosis/fix/workaround?
This is the code:
var bootstrapContext = ClaimsPrincipal.Current.Identities.First().BootstrapContext as BootstrapContext;
UserAssertion userAssertion = new UserAssertion(bootstrapContext.Token);
ClientCredential clientCred = new ClientCredential(ConfigurationManager.AppSettings["ida:Password"]);
ConfidentialClientApplication cca =
new ConfidentialClientApplication(ConfigurationManager.AppSettings["ida:ClientID"],
"https://localhost:44355", clientCred, null, null);
string[] graphScopes = { "Files.Read.All" };
AuthenticationResult result = await cca.AcquireTokenOnBehalfOfAsync(graphScopes, userAssertion, "https://login.microsoftonline.com/common/oauth2/v2.0");
This is the stack trace:
{"Message":"An error has occurred.","ExceptionMessage":"client info is null","ExceptionType":"Microsoft.Identity.Client.MsalClientException","StackTrace":" at Microsoft.Identity.Client.Internal.ClientInfo.CreateFromJson(String clientInfo)\r\n at Microsoft.Identity.Client.Internal.Requests.RequestBase.SaveTokenResponseToCache()\r\n at Microsoft.Identity.Client.Internal.Requests.RequestBase.PostTokenRequest()\r\n at Microsoft.Identity.Client.Internal.Requests.RequestBase.<RunAsync>d__33.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at Microsoft.Identity.Client.ConfidentialClientApplication.<AcquireTokenOnBehalfCommonAsync>d__16.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at Microsoft.Identity.Client.ConfidentialClientApplication.<AcquireTokenOnBehalfOfAsync>d__3.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n at Office_Add_in_ASPNET_SSO_WebAPI.Controllers.ValuesController.<Get>d__0.MoveNext() in D:\\repos\\Office-Add-in-ASP.NET-SSO\\Complete\\Office-Add-in-ASPNET-SSO-WebAPI\\Controllers\\ValuesController.cs:line 46\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Threading.Tasks.TaskHelpersExtensions.<CastToObject>d__3`1.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Filters.AuthorizationFilterAttribute.<ExecuteAuthorizationFilterAsyncCore>d__2.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__1.MoveNext()"}

Answer 1

This turned out to be a bug in Azure Active Directory V2.0 endpoint. It is fixed.