swift – ios 15 prewarming inflicting appwillLaunch methodology when prewarm is finished

We had an app in manufacturing which was reporting very excessive time to work together(tti) for ios 15 prewarm.

TTI = timewhenViewController is loaded – mainStartTime

mainStart time is measured inside AppDelegate.swift’s willFinishLaunchingWithOptions methodology like this

mainStartTime = Date()

and when first view controller is loaded we measure tti as

tti = -(mainStartTime.timeIntervalSinceNow)

We noticed that for prewarm situations mainStartTime was coming very early (approx 2 hours earlier than consumer even launches the app).

I checked on-line however discovered no documentation.
Simply needed to know can it presumably occur that prewarm is asking willFinishLaunchingWithOptions methodology whereas prewarming the app.