Model::replicate() contains laravel_through_key when loaded via HasManyThrough relationship

[levu42]

Laravel Version

11.4.0

PHP Version

8.3.6

Database Driver & Version

SQLite 3.45.3

Description

When a model is loaded through a HasManyThrough relation, it contains the laravel_through_key attribute. When I then use ->replicate() on that model, the replication also contains the laravel_through_key. This leads to me not being able to save the replication, unless I manually remove the laravel_through_key.

Steps To Reproduce

Here's a failing test in a reproducer repository:

    $organization = Organization::create();
    $department = Department::create(['organization_id' => $organization->id]);
    Employee::create(['department_id' => $department->id, 'name' => 'John']);

    $employee = $organization->employees()->first();

    $otherEmployee = $employee->replicate();
    $otherEmployee->name = 'Jane';
    $otherEmployee->save();

This gives the error message:

  SQLSTATE[HY000]: General error: 1 table employees has no column named laravel_through_key (Connection: sqlite, SQL: insert into "employees" ("name", "department_id", "laravel_through_key", "updated_at", "created_at") values (Jane, 1, 1, 2024-04-17 11:37:07, 2024-04-17 11:37:07))