Cannot upload media after upgrade, exception in RespectFileSizeLimitConfigurationAttribute

Hi!

After upgrade to CMS 12 and using Windows Authentication we cannot longer upload even the smallest of picture, the exception below occurs;

Exception: 
System.InvalidOperationException: The maximum request body size cannot be modified after the app has already started reading from the request body.
   at Microsoft.AspNetCore.Server.IIS.Core.IISHttpContext.Microsoft.AspNetCore.Http.Features.IHttpMaxRequestBodySizeFeature.set_MaxRequestBodySize(Nullable`1 value)
   at EPiServer.Cms.Shell.UI.Attributes.RespectFileSizeLimitConfigurationAttribute.OnAuthorization(AuthorizationFilterContext context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.InvokeFilterPipelineAsync()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at ElmahCore.Mvc.ErrorLogMiddleware.InvokeAsync(HttpContext context)
   at ElmahCore.Mvc.ErrorLogMiddleware.InvokeAsync(HttpContext context)
   at Microsoft.AspNetCore.Authorization.Policy.AuthorizationMiddlewareResultHandler.HandleAsync(RequestDelegate next, HttpContext context, AuthorizationPolicy policy, PolicyAuthorizationResult authorizeResult)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.ResponseCaching.ResponseCachingMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.Localization.RequestLocalizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Found this in the console:

The store was queried with a [string] but the entity id is a [undefined]

If found this so it looks like Optimizely is setting the size if there is a UploadOption

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
    public class RespectFileSizeLimitConfigurationAttribute : Attribute, IAuthorizationFilter, IFilterMetadata, IOrderedFilter
    {
        public int Order { get; set; } = 899;
        public void OnAuthorization(AuthorizationFilterContext context)
        {
            if (context == null)
            {
                throw new ArgumentNullException("context");
            }
            UploadOptions service = context.HttpContext.RequestServices.GetService<UploadOptions>();
            if (service != null)
            {
                context.HttpContext.Features.Get<IHttpMaxRequestBodySizeFeature>()!.MaxRequestBodySize = service.FileSizeLimit;
            }
        }
    }

A bug maybe?

Any ideas why this occours?

Thanks!

/Kristoffer