Adding users to roles in ASP.Net Identity with EF 6 causes new roles and users to be created

I have hit a wall on this and hope someone else has the answer, I created a Blazor app with Identity this is what my dbContext looks like:

public class ApplicationDbContext : IdentityDbContext<AppUser, AppRole, string, 
    AppUserClaim,AppUserRole,AppUserLogin,AppRoleClaim,AppUserToken>
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);
       
        builder.Entity<AppUser>().ToTable("Users");
     
        builder.Entity<AppUser>().Property(x => x.FirstName).IsRequired();
        builder.Entity<AppUser>().Property(x => x.LastName).IsRequired();
        builder.Entity<AppUser>().Property(x => x.LastLoginDate);
        builder.Entity<AppUser>().HasMany(x => x.Roles).WithOne(x=>x.User).HasForeignKey(x=>x.UserId).IsRequired();

        builder.Entity<AppUserRole>().ToTable("UserRoles").HasOne(c => c.Role).WithMany(c => c.UserRoles).HasForeignKey(c => c.UserId);

        builder.Entity<AppRole>().ToTable("Roles");
        builder.Entity<AppRole>().Property(x => x.Description);
        builder.Entity<AppRole>().HasMany(x => x.UserRoles).WithOne(e => e.Role).HasForeignKey(ur => ur.RoleId).IsRequired();
        builder.Entity<AppRole>().HasMany(x => x.RoleClaims).WithOne(e=>e.Role).HasForeignKey(x=>x.RoleId).IsRequired();
        
        builder.Entity<AppRoleClaim>().ToTable("RoleClaims");
        builder.Entity<AppRoleClaim>().HasOne(x => x.Role);

        builder.Entity<AppUserClaim>().ToTable("UserClaims");            
    }
}

And in my program.cs, I have this code:

builder.Services.AddIdentity<AppUser, AppRole>()
            .AddEntityFrameworkStores<ApplicationDbContext>();
builder.Services.AddTransient<RoleManager<AppRole>>();

Here are my Identity classes:

public class AppRole:IdentityRole
{ 
    public string? Description { get; set; }
    public virtual ICollection<AppUserRole>? UserRoles { get; set; }
    public virtual ICollection<AppRoleClaim>? RoleClaims { get; set; }

    public AppRole()
    {
    }
}

public class AppRoleClaim : IdentityRoleClaim<string>
{
    public virtual AppRole Role { get; set; }

    public AppRoleClaim()
    {
        Role = new AppRole();
    }
}

public class AppUser : IdentityUser
{
    public string FirstName { get; set; } 
    public string LastName { get; set; }
    public DateTimeOffset? LastLoginDate { get; set; }
    public byte[]? Photo { get; set; }
    public virtual ICollection<AppUserRole> Roles { get; set; }

    public AppUser()
    {
        FirstName = "";
        LastName = "";
        Roles = new List<AppUserRole>(); 
    }
}

public class AppUserClaim : IdentityUserClaim<string>
{
}

public class AppUserLogin : IdentityUserLogin<string>
{
}

public class AppUserRole : IdentityUserRole<string>
{
    public virtual AppUser User { get; set; }
    public virtual AppRole Role { get; set; }

    public AppUserRole()
    {
        User = new AppUser();
        Role = new AppRole();
    }
}

public class AppUserToken : IdentityUserToken<string>
{
}

And this is my table structure:

And finally my question , when I call UserManager.CreateAsync(NewUser) a user is correctly created, however when I try to add the newly created user to a role for example the admin role like so await UserManager.AddToRoleAsync(NewUser, "Admin"); it does not throw any error, but what happens is it creates a new user with null user name, first name etc and it adds a new role to the roles table with a null Name and null normalized name. Then it adds that role to the UserRoles table. All without any errors.

According to MS Documentation this should create one new user and add that user to the Admin role. Docs I built this from are here https://learn.microsoft.com/en-us/aspnet/core/security/?view=aspnetcore-6.0

After doing some digging today I figured out what was going on. Have a look at my AppUserRole class

public class AppUserRole : IdentityUserRole<string>
{
    public virtual AppUser User { get; set; }
    public virtual AppRole Role { get; set; }
    public AppUserRole()
    {
        User = new AppUser();
        Role = new AppRole();
    }
}

Since I was newing up a new AppUser() and a new AppRole() they in turn were calling the base class constructors in which IdentityRole sets its Id property to a new Guid the same thing happens when the constructor of IdentityUser is called. I found that out by looking at the AspNetCore.Identity source code. So EntityFramework was correctly doing its job, it saw a brand new AppUserRole with a new IdentityUser and new IdentityRole and since these were navigation properties to AppRole it created them in the database.

TLDR The fix was to make the navigation properties in the AppUserRole class nullable and not new them up in the constructor as in below:

public class AppUserRole : IdentityUserRole<string>
{
    public virtual AppUser? User { get; set; }
    public virtual AppRole? Role { get; set; }
    public AppUserRole()
    {
        
    }
}