aspnetcore: AspNetCore 2.1-preview2 - System.Text.DecoderFallbackException

Hi,

I recently upgraded my code from asp.net core 2.0 to asp.net core 2.1-preview2. Since we upgraded we are encountering a crash in the production (for some requests) which never occurred before for the same code:

System.Text.DecoderFallbackException · Unable to translate bytes [C7] at index 829 from specified code page to Unicode.
System.Text.DecoderExceptionFallbackBuffer.Throw(byte[] bytesUnknown, int index)	
System.Text.DecoderExceptionFallbackBuffer.Fallback(byte[] bytesUnknown, int index)	
System.Text.DecoderFallbackBuffer.InternalFallback(byte[] bytes, Byte* pBytes, ref Char* chars)	
System.Text.UTF8Encoding.GetChars(Byte* bytes, int byteCount, Char* chars, int charCount, DecoderNLS baseDecoder)	
System.Text.DecoderNLS.GetChars(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex, bool flush)	
System.Text.DecoderNLS.GetChars(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex)	
Microsoft.AspNetCore.WebUtilities.HttpRequestStreamReader.ReadIntoBuffer()	
Microsoft.AspNetCore.WebUtilities.HttpRequestStreamReader.Read(char[] buffer, int index, int count)	
Newtonsoft.Json.JsonTextReader.ReadData(bool append, int charsRequired)	
Newtonsoft.Json.JsonTextReader.ParseValue()	
Newtonsoft.Json.JsonTextReader.Read()	
Newtonsoft.Json.JsonReader.ReadForType(JsonContract contract, bool hasConverter)	
Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, bool checkAdditionalContent)	
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()	
Microsoft.AspNetCore.Mvc.Formatters.JsonInputFormatter+<ReadRequestBodyAsync>d__17.MoveNext()	
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()	
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)	
System.Runtime.CompilerServices.TaskAwaiter<TResult>.GetResult()	
Microsoft.AspNetCore.Mvc.ModelBinding.Binders.BodyModelBinder+<BindModelAsync>d__7.MoveNext()	
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()	
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)	
Microsoft.AspNetCore.Mvc.ModelBinding.ParameterBinder+<BindModelAsync>d__11.MoveNext()	
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()	
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)	
System.Runtime.CompilerServices.TaskAwaiter<TResult>.GetResult()	
Microsoft.AspNetCore.Mvc.Internal.ControllerBinderDelegateProvider+<>c__DisplayClass0_0+<<CreateBinderDelegate>g__Bind|0>d.MoveNext()	
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()	
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)	
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker+<InvokeInnerFilterAsync>d__13.MoveNext()	
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()	
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)	
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker+<InvokeNextExceptionFilterAsync>d__24.MoveNext()

It seems request parsing is failing which wasn’t happening before. Can’t even log the request model as crash occurs before the controller action is called.