When an iPhone user specifies a refresh interval in the widget settings, for example, 15 minutes, he expects the widget to refresh its content every 15 minutes and show new content.
But Apple and iOS don't think so!
What's really going on?
The widget asks iOS to update it at a specific time.
iOS almost always updates the widget and everything is fine. But sometimes iOS may not update the widget right now.
iOS decides when to update depends on battery, network, CPU usage and other factors. The widget cannot influence this.
The widget only says "iOS please update me". But only iOS decides when to update.
So, "12:30 requested an iOS update" means that the widget has requested an update from iOS, and now it can only wait for iOS to update it.
Apps can update their widgets without restriction only when the user is using the app itself.
If the user closes the app, widgets will only be able to update self content when iOS decides to allow it.
Proof links: Apple Documentation, Apple Developers Forum 1, Apple Developers Forum 2