My game runs fine in any other aspect of the game, but since upgrading to the latest iOS 11.4.1, I have noticed performance issues where graphics are lagging to almost 1 fps or less, sometimes crashing the game, once I enter Raid or Tower. I can leave the tower and the performance degradation continues until the app is restarted. I am running this on an iPad Air 2. Is this a known issue? If so are there plans to address this? This also happens on my wife's iPad Pro 13" running 11.4.1 as well when she is playing her account.