Reward ads crash IOS, but they work perfect on Android

I released a game on Google Play/App Store. No issues on Android devices. But after watching reward ad on Iphones/IPad , game crashes and restarts. The Reward ad plays all the way through but when the player taps to close ad, instead of going to the next set of events (get reward, play bonus game, etc.) game just crashes and restarts. Has anyone else had this problem?

got once, try to fixed by upgrade pod for newest version of cordova GoogleAds Plugins.

Update: Issue fixed. It was a memory allocation issue. I reduced the image size of every sprite and it works now. It wasn't incorrect google admob implementation or anything like that. Just artwork that was to big. Iphones/iPads are so darn finicky about file size. I still have crashes on a few players with old iphones and no space left in the drive. Android phones have worked perfect from day one, even with the giant files.