first_open event is not showing on Google ads console for iOS

The Ad account is connected to Firebase analytics. I can see the first_open event on Firebase Analytics dashboard, but the event is not listed on Google ad console's Analytics Events column, all other events are showing. It's a react native app. This problem is not happening for Android version. Following are the configurations of iOS setup:

React Native Environment Info:
  System:
    OS: macOS 10.14
    CPU: (2) x64 Intel(R) Core(TM) i5-7200U CPU @ 2.50GHz
    Memory: 2.98 GB / 7.84 GB
    Shell: 3.2.57 - /bin/bash
  Binaries:
    Node: 10.16.0 - /usr/local/bin/node
    Yarn: 1.17.0 - /usr/local/bin/yarn
    npm: 6.9.0 - /usr/local/bin/npm
    Watchman: 4.9.0 - /usr/local/bin/watchman
  SDKs:
    iOS SDK:
      Platforms: iOS 12.1, macOS 10.14, tvOS 12.1, watchOS 5.1
  IDEs:
    Xcode: 10.1/10B61 - /usr/bin/xcodebuild
  npmPackages:
    react: 16.8.3 => 16.8.3 
    react-native: 0.59.4 => 0.59.4 
  npmGlobalPackages:
    react-native-cli: 2.0.1
    react-native: 0.59.9

AppDelegate.m code to launch the app

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#import "AppDelegate.h"

#import <React/RCTBridge.h>
#import <React/RCTBundleURLProvider.h>
#import <React/RCTRootView.h>
#import "RNSplashScreen.h"
#import <FBSDKCoreKit/FBSDKCoreKit.h>
@import Firebase;
#import "RNFirebaseNotifications.h"
#import "RNFirebaseMessaging.h"
#import "RCTLinkingManager.h"

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  RCTBridge *bridge = [[RCTBridge alloc] initWithDelegate:self launchOptions:launchOptions];
  RCTRootView *rootView = [[RCTRootView alloc] initWithBridge:bridge
                                                   moduleName:@"abc"
                                            initialProperties:nil];

  rootView.backgroundColor = [[UIColor alloc] initWithRed:1.0f green:1.0f blue:1.0f alpha:1];

  self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
  UIViewController *rootViewController = [UIViewController new];
  rootViewController.view = rootView;
  self.window.rootViewController = rootViewController;
  [self.window makeKeyAndVisible];