Since iOS 15 the logic for displaying push notifications has changed. Push notifications were always displayed immediately upon receipt but starting with iOS 15 the user can set up a delayed display of notifications according to their own schedule and Focus Mode. In these cases iOS will put the notification in the Notification Summary and show it according to the schedule or after Focus Mode ends.
The Push Delivered status will be sent by the push library immediately after delivery not at the moment the notification is displayed.
Apple gives developers the opportunity to specify the urgency of notifications. For transactions and one-time passwords the Time-Sensitive interruption level is best suited – notifications of this level are displayed immediately upon receipt. For marketing notifications the Active level is suitable which is subject to the rules of delayed display.
After the first display of a Time-Sensitive level notification iOS will ask the user for permission to continue displaying such notifications, so it is important to specify the Time-Sensitive level only for urgent notifications to increase the chance of obtaining user permission.
If you do not specify the interruption level the Active level is applied.
On phones with previous versions of iOS the interruption level will be ignored and notifications will be displayed as usual.