게시판 정보를 props 로 넘겨줄 때 오류가 납니다.

export default async function List(){

    const db = (await connectDB).db("forum");
    let result = await db.collection('post').find().toArray()

    return(
        <ul className="list-bg">
            <ListItem result={result}/>
        
    )
}

export default function DetailLink({result}){

    return (
        <div>
            {
                result.map(el =>{
                        return <li key={el._id} className="list-item">
                            <Link prefetch={false} href={`/detail/${el._id}`}>
                                <h4>{el.title}</h4>
                            </Link>
                            <Link href={'/edit/' + el._id}>수정</Link>
                            <span onClick={()=>{
                                fetch('/api/post/delete', {method : 'DELETE' , body: el._id})
                            }}  >삭제</span>
                            <p>{el.content}</p>
                        
                        }
                    )
            }
        </div>
    )
}

Warning: Only plain objects can be passed to Client Components from Server Components. Objects with toJSON methods are not supported. Convert it manually to a simple value before passing it to props.
  {_id: {}, title: "안녕요", content: "반가워워"}
        ^^
Warning: Only plain objects can be passed to Client Components from Server Components. Objects with toJSON methods are not supported. Convert it manually to a simple value before passing it to props.
  {_id: {}, content: "두번째글다시시", title: ...}
        ^^
Warning: Only plain objects can be passed to Client Components from Server Components. Objects with toJSON methods are not supported. Convert it manually to a simple value before passing it to props.
  {_id: {}, title: "세번째글", content: ...}
        ^^
Warning: Only plain objects can be passed to Client Components from Server Components. Objects with toJSON methods are not supported. Convert it manually to a simple value before passing it to props.
  {_id: {}, title: "1234", content: ...}
        ^^
Warning: Only plain objects can be passed to Client Components from Server Components. Objects with toJSON methods are not supported. Convert it manually to a simple value before passing it to props.
  {_id: {}, title: "1234", content: ...}
        ^^
Warning: Only plain objects can be passed to Client Components from Server Components. Objects with toJSON methods are not supported. Convert it manually to a simple value before passing it to props.
  {_id: {}, title: "글 제목 확인", content: ...}
        ^^

왜 선생님 강의 영상에서는 그냥 toString안해주고 result 써도 오류없이 되는데 저는 안될까요..?