Im experiencing the same issue as well. Any body a solution yet?
Im on iOS 12.1
Ionic:
ionic (Ionic CLI) : 4.1.2 (/usr/local/lib/node_modules/ionic)
Ionic Framework : ionic-angular 3.9.2
@ionic/app-scripts : 3.1.11
Cordova:
cordova (Cordova CLI) : 7.1.0
Cordova Platforms : android 6.4.0, ios 4.5.5
Cordova Plugins : cordova-plugin-ionic-webview 1.2.1, (and 23 other plugins)