Troubles with .NET Core 1 on Linux after migration from RC1 (Error 500 for some API clients)

Hello! I'm using RC1 for few months with success in production. After migration from RC1 to .NET Core 1some clients receive 500 Error after POST request to my WEB API.

Details: Ubuntu 14.04 + nginx/1.4.6 + SSL+ .NET Core 1.0.0-preview2-003121

Log:

[Error] Connection id ""0HKU79RRNF33P"": An unhandled exception was thrown by the application.
System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values.
Parameter name: length
   at Microsoft.Extensions.Primitives.StringSegment..ctor(String buffer, Int32 offset, Int32 length)
   at Microsoft.AspNetCore.Mvc.Formatters.MediaType.CreateMediaTypeSegmentWithQuality(String mediaType, Int32 start)
   at Microsoft.AspNetCore.Mvc.Formatters.Internal.AcceptHeaderParser.GetMediaTypeWithQualityLength(String input, Int32 start, MediaTypeSegmentWithQuality& result)
   at Microsoft.AspNetCore.Mvc.Formatters.Internal.AcceptHeaderParser.TryParseValue(String value, Int32& index, MediaTypeSegmentWithQuality& parsedValue)
   at Microsoft.AspNetCore.Mvc.Formatters.Internal.AcceptHeaderParser.ParseAcceptHeader(IList`1 acceptHeaders, IList`1 parsedValues)
   at Microsoft.AspNetCore.Mvc.Internal.ObjectResultExecutor.GetAcceptableMediaTypes(MediaTypeCollection contentTypes, HttpRequest request)
   at Microsoft.AspNetCore.Mvc.Internal.ObjectResultExecutor.SelectFormatter(OutputFormatterWriteContext formatterContext, MediaTypeCollection contentTypes, IList`1 formatters)
   at Microsoft.AspNetCore.Mvc.Internal.ObjectResultExecutor.ExecuteAsync(ActionContext context, ObjectResult result)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeResultAsync>d__32.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeResultFilterAsync>d__31.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeAllResultFiltersAsync>d__29.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeResourceFilterAsync>d__23.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeAsync>d__18.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Hosting.Internal.RequestServicesContainerMiddleware.<Invoke>d__3.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Frame`1.<RequestProcessingAsync>d__2.MoveNext()
[Information] Request finished in 55.2395ms 200

Can anyone help me to resolve this issue? Thanks!