IOS http request loads slower at the first call of the scene

Hi
Somehow the http request takes a lot of time while opening the scene for the first time on IOS. The scene gets called again later in the process of the app (there are a few scenes between it). But for some reasons the http request returns the data immediately like it should. In the first calling of the screen it takes at least 5 sec. Why is this happening because it works fine on android.