How to resolve EF Core migration error with HiLo?

A little background. I'm using:

• .Net Core 2.2.3
• Postgres as my database
• Npgsql.EntityFramworkCore.PostgreSQL 2.20
• EntityFramwork as ORM

and I'm using that simple HiLo sequence declaration in my context.

protected override void OnModelCreating(ModelBuilder modelBuilder) {
    base.OnModelCreating(modelBuilder);
    modelBuilder.ForNpgsqlUseSequenceHiLo();
}

Which creates my migration files as follows:

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.CreateSequence(
        name: "EntityFrameworkHiLoSequence",
        incrementBy: 10);

    migrationBuilder.CreateTable(
        name: "AspNetRoles",
        columns: table => new
        {
            Id = table.Column<int>(nullable: false)
                .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.SequenceHiLo),
            Name = table.Column<string>(maxLength: 256, nullable: true),
            NormalizedName = table.Column<string>(maxLength: 256, nullable: true),
            ConcurrencyStamp = table.Column<string>(nullable: true)
        },
        constraints: table =>
        {
            table.PrimaryKey("PK_AspNetRoles", x => x.Id);
        });
    // other tables code goes here... All key has
    // .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.SequenceHiLo)
}

Everything works, but HiLo is assigning strange IDs (but still unique). How strange? Let me explain. For example:

I have tables

• Orders
• OrderItems
• Roles (completely unrelated to previous).

And I do a simple seed to database which assigns IDs as follow:

Orders:

• 1 MyOrder1

OrderItem:

• 2 MyOrderItem1
• 3 MyOrderItem2
• 4 MyOrderItem3

Roles:

• 5 MyRole1
• 6 MyRole2

So it looks like it have shared HiLo for all tables. I thought that It's HiLo per table.

Also I get error when I use clean new migration and do:

• dotnet ef database drop && dotnet ef database update

I've got error (translated to English from Polish):

42P07: relation "EntityFrameworkHiLoSequence" already exist

@UPDATE

Thanks to @jpgrassi I found solution for strange IDs. I've made named HiLo for every model. It looks like this:

protected override void OnModelCreating(ModelBuilder modelBuilder) {
    base.OnModelCreating(modelBuilder);

    modelBuilder.Entity<OrderItem>()
        .Property(b => b.Id)
        .ForNpgsqlUseSequenceHiLo("OrderItemsHiLo");

    modelBuilder.Entity<Order>()
        .Property(b => b.Id)
        .ForNpgsqlUseSequenceHiLo("OrdersHiLo");
    // More sequences goes below...
}

Now it all sound logical. But... I have new error:

42P07: relation "OrderItemsHiLo" already exist

My Up section:

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.CreateSequence(
        name: "OrderItemsHiLo",
        incrementBy: 10);
    // more code...
}

And in my Down section in migration I have:

migrationBuilder.DropSequence(name: "OrderItemsHiLo");

My question is: Why this error is thrown on clean migration and how to get rid of it?

@UPDATE

I just removed that line and it resolved my second issue. Stupid me...

_context.Database.EnsureCreatedAsync();