Blazor concurrency problem using Entity Framework Core

My goal

I want to create a new IdentityUser and show all the users already created through the same Blazor page. This page has:

1. a form through you will create an IdentityUser
2. a third-party's grid component (DevExpress Blazor DxDataGrid) that shows all users using UserManager.Users property. This component accepts an IQueryable as a data source.

Problem

When I create a new user through the form (1) I will get the following concurrency error:

InvalidOperationException: A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread-safe.

I think the problem is related to the fact that CreateAsync(IdentityUser user) and UserManager.Users are referring the same DbContext

The problem isn't related to the third-party's component because I reproduce the same problem replacing it with a simple list.

Step to reproduce the problem

1. create a new Blazor server-side project with authentication

2. change Index.razor with the following code:

   @page "/"
   
   <h1>Hello, world!</h1>
   
   number of users: @Users.Count()
   <button @onclick="@(async () => await Add())">click me</button>
   <ul>
   @foreach(var user in Users) 
   {
       <li>@user.UserName</li>
   }
   </ul>
   
   @code {
       [Inject] UserManager<IdentityUser> UserManager { get; set; }
   
       IQueryable<IdentityUser> Users;
   
       protected override void OnInitialized()
       {
           Users = UserManager.Users;
       }
   
       public async Task Add()
       {
           await UserManager.CreateAsync(new IdentityUser { UserName = $"test_{Guid.NewGuid().ToString()}" });
       }
   }
   

What I noticed

• If I change Entity Framework provider from SqlServer to Sqlite then the error will never show.

System info

• ASP.NET Core 3.1.0 Blazor Server-side
• Entity Framework Core 3.1.0 based on SqlServer provider

What I have already seen

• Blazor A second operation started on this context before a previous operation completed: the solution proposed doesn't work for me because even if I change my DbContext scope from Scoped to Transient I still using the same instance of UserManager and its contains the same instance of DbContext
• other guys on StackOverflow suggests creating a new instance of DbContext per request. I don't like this solution because it is against Dependency Injection principles. Anyway, I can't apply this solution because DbContext is wrapped inside UserManager
• Create a generator of DbContext: this solution is pretty like the previous one.
• Using Entity Framework Core with Blazor

Why I want to use IQueryable

I want to pass an IQueryable as a data source for my third-party's component because its can apply pagination and filtering directly to the Query. Furthermore IQueryable is sensitive to CUD operations.