Step 1: Describe your environment
Step 2: Describe the problem
OnUserEarnedRewardevent is called after OnAdClosedin editor. When built to device OnUserEarnedRewardis called before OnAdClosed. After peeking around quite a bit online it seems as though OnUserEarnedRewardshould be called prior to OnAdClosedalways. If this is the case the implementation in editor should reflect this :)
On top of what @thsbrown has mentioned, the RewardedAd prefab should have a button at all times to allow the user to close the ad without getting the reward.
I am using Google Mobile Ads Unity Plugin v6.1.0 and the issue described above is reproducible on my end as well. OnUserEarnedReward ought to be called before OnAdClosed
Most helpful comment
On top of what @thsbrown has mentioned, the RewardedAd prefab should have a button at all times to allow the user to close the ad without getting the reward.