Interstitial OnAdClosed event not firing for iOS on Unity when "Optimize Initialization" / "Optimize ad loading" enabled

[REQUIRED] Step 1: Describe your environment

• Unity version: 2021.3.12f1
• Google Mobile Ads Unity plugin version: 1.2.172 / 1.2.174
• Platform: iOS
• Platform OS version: All iOS Versions
• Any specific devices issue occurs on: iPhone 6s
• Mediation ad networks used, and their versions: N/A

[REQUIRED] Step 2: Describe the problem

When enabling “Optimize Initialization” and “Optimize ad loading” from the “Google Mobile Ads Settings” inspector panel, OnAdClosed is not fired after an interstitial ad is closed.

Note that OnAdClosed fires successfully for Android.

Initially I thought it might be an issue with OnAdClosed not being fired on the main (UI) thread, but after closer inspection it appears to not fire at all.

Note that you can get to the “Google Mobile Ads Settings” scene by going to “Assets” / “Google Mobile Ads” / “Settings”, then opening the “Inspector” tab.

Steps to reproduce:

1. Create a new project.
2. Select “Optimize Initialization” and “Optimize ad loading” on admob
3. Create a interstitial that fires, and setup a callback to OnAdClosed
4. Notice that it does not fire on iOS (does fire on Android)

Relevant Code:

        _interstitialAd = new InterstitialAd("-----AD_ID------");
        _interstitialAd.OnAdClosed += HandleRewardedInterstitialClosed;
        _interstitialAd.LoadAd(createAdRequest());
        _interstitialAd.Show();

        private void HandleRewardedInterstitialClosed(object sender, EventArgs args)
        {
            Logger.log("Called")
        }

[lucianocheng]

Double checking my AndroidManifest.xml

Unclear why AndroidManifest.xml is relevant since this is an iOS issue? Issue does not appear on Android.

[lucianocheng]

@NVentimiglia was this ever resolved?