iOS Bug: Ad callbacks not triggering (reproducible)

[REQUIRED] Step 1: Describe your environment

• Unity version: 2021.2.1, 2021.1.1
• Google Mobile Ads Unity plugin version: 6.1.2
• Platform: iOS
• Platform OS version: iOS 15.2, 15.1
• Any specific devices issue occurs on: any iOS device
• Mediation ad networks used, and their versions: none

[REQUIRED] Step 2: Describe the problem

Steps to reproduce:

AdMob Event Issue (2021.2.1).zip

1. build and run the provided project on iOS
2. open the app and wait for AdMob to initialize and load an ad
3. press the ‘Show Ad’ button
4. press the X button on the interstitial test ad to close it
5. immediately open the iOS control center (swipe down from the right side of the top edge of the screen)

Expected result: the ad closes and the OnAdClosed callback is triggered Actual result: the ad closes but the OnAdClosed callback is NOT triggered

Here are two videos:

• the ‘control’: the app can load an ad, open and close it, and all the associated callbacks function properly https://user-images.githubusercontent.com/11318436/146649288-935c6fe7-e4de-421c-b6a2-e5708d9f70a7.mov
• the ‘problem’: demonstrating the bug, folowing steps 2-5 from above https://user-images.githubusercontent.com/11318436/146649321-608ab374-c38b-4b66-a041-af0757dd691e.mov

Notes and findings:

• on iOS, by default, opening the control center (or notifications, or multitasking) will pause the game and make it not in focus (can be seen by using MonoBehaviour.OnApplicationPause and MonoBehaviour.OnApplicationFocus)
• by enabling the ‘Enable Custom Background Behaviours’ option (in Player Settings > Other Settings > Configuration), the game won’t be paused when the control center is opened, but it will lose focus (according to the two methods from the previous point); this bug still occurs even with this option enabled
• settings the game to pause while an ad is running with MobileAds.SetiOSAppPauseOnBackground(true); does not solve this issue either; the same thing happens and the game remains paused
• I don’t know if it is relevant, but this bug occurs with both test ads and real ads (in a launched product)
• the example project uses a bare-bones implementation of AdMob, using the sample code from this repository and the official guide
• I haven’t tested it, but I think this issue happens with reward ads as well (OnAdClosed and maybe even OnUserEarnedReward with proper timing)
• the issue doesn’t seem to occur on Android devices by opening the notifications pull-down menu, might be because that doesn’t pause the game or the ad

[emcmeem]

This problem is still not solved for me too

[NVentimiglia]

@PokerDawg I implemented the suggested fix of wrapping the callback handler within ExecuteInUpdate(). The result looked correct to me (image below). I will be closing this issue, please feel free to reopen if there is something I missed or you are still stuck.