Mongoose "Can't save() the same doc multiple times in parallel" on related data push when calling save function in same instance of model

Question

Basically I have two collections with one two many relationship question and answers i am trying to populate data these related collections.

Once the question is saved, I am trying to save multiple answers related to that question. Here is the code that i have written so for to add multiple answer(where answers is a array containing object inside).

let question = await Question.findOne({_id: question_id});
    //Here answer is a array containing objects
    answers.forEach(async function (answer, i) {

        let newAnswer = new Answer({
            question: question._id,
            answers: answer.ans,
        });
        await newAnswer.save();

        await question.answers.push(newAnswer);
        await question.save();
    });

However this code saves only one reference to the question collection and throws error

"Can't save() the same doc multiple times in parallel. Document: 5bf7cb66f4f14a5bb6a2bf6c {"name":"ParallelSaveError"}"

Please help me to find out the correct method to solve this problem thanks.

Here is the Model

const questionSchema = mongoose.Schema({
    question: {
        type: String,
        required: true,
        unique: true
    },
    answers: [{type: mongoose.Schema.ObjectId, ref: 'Answer'}]
});

const answerSchema = mongoose.Schema({
    question: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'Question'
    },
    answers: {
        type: String,
        required: true
    }
});