Ionic 5 - iOS Rendering

i’m using Ionic 5 to develop my application. If i run the application forcing mode on ‘md’ in the browser simulation it works well (User Interface) on android or ios device, but if i run the application with --lab options the application is not showed well on iOS Simulator. Same thing on phisical devices. On android all work well but on iOS the graphic is not the same, despite i have forced md mode in IonicModule.forRoot. Why?