ASP .NET Core 2.1 Identity: UserRoles is null - razor

Question

In my Razor web app, I've tried to get a list of users and their roles the following ways:
_userManager.GetUsersInRoleAsync(role).Result;
_dbContext.Users.Include(u => u.UserRoles).ThenInclude(u => u.Role);
_userManager.Users.Include(u => u.UserRoles).ThenInclude(ur => ur.Role).ToList();
And UserRoles is always null. Any idea what I'm doing wrong?
Here is my Startup:
services.AddIdentity<ApplicationUser, ApplicationRole>()
.AddDefaultUI()
.AddDefaultTokenProviders()
.AddEntityFrameworkStores<ApplicationDbContext>();
Here is my model:
public class ApplicationUser : IdentityUser
{
public virtual ICollection<ApplicationUserRole> UserRoles { get; set; }
}
public class ApplicationRole : IdentityRole
{
public virtual ICollection<ApplicationUserRole> UserRoles { get; set; }
}
public class ApplicationUserRole : IdentityUserRole<string>
{
public virtual ApplicationUser User { get; set; }
public virtual ApplicationRole Role { get; set; }
}
Here is my OnModelCreating:
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<ApplicationUser>(au =>
{
au.HasMany(e => e.UserRoles).WithOne(e => e.User).HasForeignKey(ur => ur.UserId).IsRequired();
});
builder.Entity<ApplicationRole>(ar =>
{
ar.HasMany(e => e.UserRoles).WithOne(e => e.Role).HasForeignKey(ur => ur.RoleId).IsRequired();
});
builder.Entity<ApplicationUserRole>(aur =>
{
aur.HasOne(ur => ur.Role).WithMany(r => r.UserRoles).HasForeignKey(ur => ur.RoleId).IsRequired();
aur.HasOne(ur => ur.User).WithMany(r => r.UserRoles).HasForeignKey(ur => ur.UserId).IsRequired();
});
}