Why Are Real Notification Emails Not Being Sent in My Firebase Cloud Function Like Test Emails?

I'm using a Firebase Cloud Function with Nodemailer to send emails for notifications. My sendTestEmail function successfully sends emails when triggered from a test button, but real notifications (e.g., follow notifications or session requests) get created in Firestore and sometimes trigger push notifications without sending any emails.

I have verified the following:
• sendTestEmail unconditionally calls transporter.sendMail when a user has an email address.
• The real notifications code might only call sendMail based on notificationSettings.emailNotifications, and even forcing this condition off doesn't trigger email sending or logging.
• Cloud Functions logs show no indication that the email-sending code is being executed for real notifications.

Below is my sendTestEmail function code:

JAVASCRIPTCopied
const functions = require('firebase-functions');
const admin = require('firebase-admin');
const nodemailer = require('nodemailer');

// Create a transporter using Namecheap SMTP
const transporter = nodemailer.createTransport({
  host: 'mail.privateemail.com',
  port: 465,
  secure: true,
  auth: {
    user: functions.config().email.user,
    pass: functions.config().email.password
  }
});

// Test email function
exports.sendTestEmail = functions.https.onCall(async (data, context) => {
  if (!context.auth) {
    throw new functions.https.HttpsError('unauthenticated', 'You must be signed in to send test notifications');
  }

  const { userId, notificationType = 'test' } = data;
  if (!userId) {
    throw new functions.https.HttpsError('invalid-argument', 'User ID is required');
  }

  // 1. Get user info from Firestore
  const userDoc = await admin.firestore().collection('userInfo').doc(userId).get();
  if (!userDoc.exists) {
    throw new functions.https.HttpsError('not-found', 'User not found');
  }

  const userData = userDoc.data();
  
  // 2. Create a notification in Firestore
  const notificationRef = admin.firestore().collection('notifications').doc();
  const notificationData = {
    userId,
    type: notificationType,
    createdAt: admin.firestore.FieldValue.serverTimestamp(),
    read: false,
    title: 'Test Notification',
    message: 'This is a test notification'
  };
  await notificationRef.set(notificationData);

  // 3. Send email if userData.email exists
  if (userData.email) {
    const mailOptions = {
      from: 'Support <support@lurk.chat>',
      to: userData.email,
      subject: `Test notification: ${notificationData.title}`,
      html: '<h2>This is a test email</h2>'
    };

    try {
      const result = await transporter.sendMail(mailOptions);
      console.log('Test email sent:', {
        messageId: result.messageId,
        response: result.response
      });
    } catch (error) {
      console.error('Error sending test email:', error);
    }
  }
});

And here is the part of my code handling real notifications:

JAVASCRIPTCopied
import React, { useState, useEffect } from 'react';
import {
  Box,
  Container,
  VStack,
  HStack,
  Text,
  Button,
  Heading,
  Flex,
  Badge,
  IconButton,
  Avatar,
  Icon,
  Link,
  Image,
} from '@chakra-ui/react';
import { collection, query, where, onSnapshot, orderBy, updateDoc, doc, addDoc, deleteDoc, serverTimestamp, getDoc } from 'firebase/firestore';
import { db } from '../../firebase';
import { useAuth } from '../../contexts/AuthContext';
import { CheckIcon, ArrowBackIcon } from '@chakra-ui/icons';
import { useNavigate, Link as RouterLink } from 'react-router-dom';
import { useToast } from '@chakra-ui/react';
import { MdAccessTime } from 'react-icons/md';
import { FaDollarSign } from 'react-icons/fa';
import { TestEmail } from '../../Components/TestEmail';
import { getFunctions, httpsCallable } from 'firebase/functions';

// ...additional notification handling code

I suspect that in my real notification flow, the code to execute transporter.sendMail might be missing or not reached. How can I modify or debug my real notification logic so that emails are sent just like in sendTestEmail?