diff --git a/lib/resource/resource.ex b/lib/resource/resource.ex
index 8a0ff52..67577e7 100644
--- a/lib/resource/resource.ex
+++ b/lib/resource/resource.ex
@@ -634,7 +634,7 @@ defmodule AshGraphql.Resource do
       |> Enum.filter(& &1.writable?)
       |> Enum.map(fn attribute ->
         allow_nil? =
-          attribute.allow_nil? || attribute.default || type == :update ||
+          attribute.allow_nil? || attribute.default || type == :update || attribute.generated? ||
             (type == :create && attribute.name in action.allow_nil_input)
 
         explicitly_required = attribute.name in action.require_attributes
@@ -642,7 +642,7 @@ defmodule AshGraphql.Resource do
         field_type =
           attribute.type
           |> field_type(attribute, resource, true)
-          |> maybe_wrap_non_null(explicitly_required || attribute_required?(attribute))
+          |> maybe_wrap_non_null(explicitly_required || not allow_nil?)
 
         %Absinthe.Blueprint.Schema.FieldDefinition{
           description: attribute.description,
@@ -663,7 +663,7 @@ defmodule AshGraphql.Resource do
             type =
               argument.type
               |> field_type(argument, resource, true)
-              |> maybe_wrap_non_null(attribute_required?(argument))
+              |> maybe_wrap_non_null(argument_required?(argument))
 
             %Absinthe.Blueprint.Schema.FieldDefinition{
               identifier: argument.name,
@@ -689,7 +689,7 @@ defmodule AshGraphql.Resource do
               identifier: argument.name,
               module: schema,
               name: to_string(argument.name),
-              type: maybe_wrap_non_null(type, attribute_required?(argument)),
+              type: maybe_wrap_non_null(type, argument_required?(argument)),
               __reference__: ref(__ENV__)
             }
         end
@@ -883,7 +883,7 @@ defmodule AshGraphql.Resource do
       type =
         argument.type
         |> field_type(argument, resource, true)
-        |> maybe_wrap_non_null(attribute_required?(argument))
+        |> maybe_wrap_non_null(argument_required?(argument))
 
       %Absinthe.Blueprint.Schema.FieldDefinition{
         identifier: argument.name,
@@ -1986,10 +1986,9 @@ defmodule AshGraphql.Resource do
     end
   end
 
-  defp attribute_required?(%{allow_nil?: true}), do: false
-  defp attribute_required?(%{generated?: true}), do: false
-  defp attribute_required?(%{default: default}) when not is_nil(default), do: false
-  defp attribute_required?(_), do: true
+  defp argument_required?(%{allow_nil?: true}), do: false
+  defp argument_required?(%{default: default}) when not is_nil(default), do: false
+  defp argument_required?(_), do: true
 
   # sobelow_skip ["DOS.StringToAtom"]
   defp relationships(resource, api, schema) do
diff --git a/test/create_test.exs b/test/create_test.exs
index 38656d3..23f46de 100644
--- a/test/create_test.exs
+++ b/test/create_test.exs
@@ -58,6 +58,56 @@ defmodule AshGraphql.CreateTest do
            } = result
   end
 
+  test "a create with a managed relationship works with many_to_many and [on_lookup: :relate, on_match: :relate]" do
+    resp =
+      """
+      mutation CreatePostWithCommentsAndTags($input: CreatePostWithCommentsAndTagsInput) {
+        createPostWithCommentsAndTags(input: $input) {
+          result{
+            text
+            comments(sort:{field:TEXT}){
+              text
+            }
+            tags(sort:{field:NAME}){
+              name
+            }
+          }
+          errors{
+            message
+          }
+        }
+      }
+      """
+      |> Absinthe.run(AshGraphql.Test.Schema,
+        variables: %{
+          "input" => %{
+            "text" => "foobar",
+            "comments" => [
+              %{"text" => "foobar"},
+              %{"text" => "barfoo"}
+            ],
+            "tags" => [%{"name" => "test"}, %{"name" => "tag"}]
+          }
+        }
+      )
+
+    assert {:ok, result} = resp
+
+    refute Map.has_key?(result, :errors)
+
+    assert %{
+             data: %{
+               "createPostWithCommentsAndTags" => %{
+                 "result" => %{
+                   "text" => "foobar",
+                   "comments" => [%{"text" => "barfoo"}, %{"text" => "foobar"}],
+                   "tags" => [%{"name" => "tag"}, %{"name" => "test"}]
+                 }
+               }
+             }
+           } = result
+  end
+
   test "a create with arguments works" do
     resp =
       """
diff --git a/test/support/api.ex b/test/support/api.ex
index 2998078..af070ae 100644
--- a/test/support/api.ex
+++ b/test/support/api.ex
@@ -6,6 +6,8 @@ defmodule AshGraphql.Test.Api do
   resources do
     resource(AshGraphql.Test.Comment)
     resource(AshGraphql.Test.Post)
+    resource(AshGraphql.Test.PostTag)
+    resource(AshGraphql.Test.Tag)
     resource(AshGraphql.Test.User)
   end
 end
diff --git a/test/support/resources/post.ex b/test/support/resources/post.ex
index 02147a0..c8327b1 100644
--- a/test/support/resources/post.ex
+++ b/test/support/resources/post.ex
@@ -17,6 +17,13 @@ defmodule AshGraphql.Test.Post do
 
     managed_relationships do
       managed_relationship :with_comments, :comments
+
+      managed_relationship :with_comments_and_tags, :comments,
+        type_name: :create_post_comment_with_tag
+
+      managed_relationship :with_comments_and_tags, :tags,
+        lookup_with_primary_key?: false,
+        lookup_identities: [:name]
     end
 
     mutations do
@@ -24,6 +31,7 @@ defmodule AshGraphql.Test.Post do
       create :upsert_post, :upsert, upsert?: true
 
       create :create_post_with_comments, :with_comments
+      create :create_post_with_comments_and_tags, :with_comments_and_tags
 
       update :update_post, :update
       update :update_best_post, :update, read_action: :best_post, identity: false
@@ -55,6 +63,14 @@ defmodule AshGraphql.Test.Post do
       change(manage_relationship(:comments, type: :direct_control))
     end
 
+    create :with_comments_and_tags do
+      argument(:comments, {:array, :map})
+      argument(:tags, {:array, :map}, allow_nil?: false)
+
+      change(manage_relationship(:comments, on_lookup: :relate, on_no_match: :create))
+      change(manage_relationship(:tags, on_lookup: :relate, on_no_match: :create))
+    end
+
     read :paginated do
       pagination(required?: true, offset?: true, countable: true)
     end
@@ -104,5 +120,11 @@ defmodule AshGraphql.Test.Post do
   relationships do
     has_many(:comments, AshGraphql.Test.Comment)
     has_many(:paginated_comments, AshGraphql.Test.Comment, read_action: :paginated)
+
+    many_to_many(:tags, AshGraphql.Test.Tag,
+      through: AshGraphql.Test.PostTag,
+      source_field_on_join_table: :post_id,
+      destination_field_on_join_table: :tag_id
+    )
   end
 end
diff --git a/test/support/resources/post_tag.ex b/test/support/resources/post_tag.ex
new file mode 100644
index 0000000..a3b206a
--- /dev/null
+++ b/test/support/resources/post_tag.ex
@@ -0,0 +1,18 @@
+defmodule AshGraphql.Test.PostTag do
+  @moduledoc false
+
+  use Ash.Resource,
+    data_layer: Ash.DataLayer.Ets
+
+  relationships do
+    belongs_to :post, AshGraphql.Test.Post do
+      primary_key?(true)
+      required?(true)
+    end
+
+    belongs_to :tag, AshGraphql.Test.Tag do
+      primary_key?(true)
+      required?(true)
+    end
+  end
+end
diff --git a/test/support/resources/tag.ex b/test/support/resources/tag.ex
new file mode 100644
index 0000000..dd0c749
--- /dev/null
+++ b/test/support/resources/tag.ex
@@ -0,0 +1,45 @@
+defmodule AshGraphql.Test.Tag do
+  @moduledoc false
+
+  use Ash.Resource,
+    data_layer: Ash.DataLayer.Ets,
+    extensions: [AshGraphql.Resource]
+
+  graphql do
+    type(:tag)
+
+    queries do
+      get :get_tag, :read
+      list :get_tags, :read
+    end
+
+    mutations do
+      create :create_tag, :create
+      destroy :destroy_tag, :destroy
+    end
+  end
+
+  actions do
+    create :create do
+      primary?(true)
+    end
+  end
+
+  attributes do
+    uuid_primary_key(:id)
+
+    attribute(:name, :string)
+  end
+
+  identities do
+    identity(:name, [:name])
+  end
+
+  relationships do
+    many_to_many(:posts, AshGraphql.Test.Post,
+      through: AshGraphql.Test.PostTag,
+      source_field_on_join_table: :tag_id,
+      destination_field_on_join_table: :post_id
+    )
+  end
+end