Error when insert schema with embeds_many when using changeset

Questions / Help
,
1

Im getting problem with insert schema with embeds_many when using changeset
This is the product schema

defmodule Hello.Catalog.Product do
  use Ecto.Schema
  import Ecto.Changeset
  schema "products" do
    field :title, :string
    embeds_many :variants, Hello.Catalog.Variant, on_replace: :delete
    timestamps(type: :utc_datetime)
  end

  @doc false
  def changeset(product, attrs) do
    product
    |> cast(attrs, [:title])
    |> cast_embed(:variants,
      with: &Hello.Catalog.Variant.changeset/3,
      drop_param: :variants_drop,
      sort_param: :variants_sort
    )
    |> validate_required([:title])
  end
end

variant schema

defmodule Hello.Catalog.Variant do
  use Ecto.Schema
  import Ecto.Changeset
  embedded_schema do
    field :name, :string
    field :price, :decimal
    field :sku, :string
  end

  def changeset(variant, attrs, _index) do
    variant
    |> cast(attrs, [:name, :price, :sku])
    |> validate_required([:name, :price, :sku])
  end
end

When i use

Product.changeset(%Product{}, %{
  "title" => "te",
  "variants" => [
    %{"name" => "t", "price" => "1", "sku" => "a"}
  ]
})
|> Repo.insert()

It shows

** (Ecto.ChangeError) value 
`[%Hello.Catalog.Variant{id: "402143f5-e875-4976-86c0-6aeab3420946",name: "t", price: Decimal.new("1"), sku: "a"}]` 
for `Hello.Catalog.Product.variants` in `insert` does not match type
#Ecto.Embedded<%Ecto.Embedded{cardinality: :many, field: :variants, owner: Hello.Catalog.Product, related: Hello.Catalog.Variant, on_cast: nil, on_replace: :delete, unique: true, ordered: true}>

But when i insert product struct without changeset, it works

%Product{title: "T", variants: [%Variant{name: "TEST", sku: "t1", price: 1.0}]}
|> Repo.insert()

I found a related topic https://elixirforum.com/t/using-repo-insert-all-when-your-schema-has-embeds-many/14219/, but its uncleared.
Can someone explain why this changeset insert method doesnt work.