Ionic 4 Ios mode not getting applied on ios devices and its always md

I am working ionic v4 app and facing one strange issue. Whenever I run ionic cordova run ios command the app launches but platform md mode is always being applied.I have checked that I am not overriding any default setting with IonicModule.forRoot method.

If I change the config options to below code then only ios node is applied.
IonicModule.forRoot(
{
mode:‘ios’,
swipeBackEnabled: false
}
),

If I create a new temlate project from scratch then it is working as expected.

Has anyone come across this weird issue?