Lost the first item when populating to array field

[t_n_thanh_le (Tấn Thành Lê)]

I have two model User and ChatRoom.
In User model has chatrooms field like this:
@Prop({ type: [{ type: mongoose.Schema.Types.String, ref: ‘ChatRoom’ }], defaul: })
chatrooms: string;
In ChatRoom model has members field like this:
@Prop({ type: [{ type: mongoose.Schema.Types.ObjectId, ref: ‘User’ }], default: })
members: string;

My original query:

this.userModel
            .findById(userId)
            .select('name username chatrooms')
            .populate({
                path: 'chatrooms',
                select: 'name roomImage members',
            });

But if I change my query like below

this.userModel
            .findById(userId)
            .select('name username chatrooms')
            .populate({
                path: 'chatrooms',
                select: 'name roomImage members',
                populate: {
                    path: 'members',
                    select: 'name username'
                },
            });

I will lose the first member in the test_room2 which has the _id: 64d08bf77c1dbd17e493acd7