I am seeing the same issue... push notifications worked perfectly up until a few days ago, then they just stopped. I'm trying to find out what Required:0.00, Observed:1.00" is from the console message, it seems like it would be helpful, but I can't find anything on it. I created a support ticket... I'll post the results here.

I don't know if throttling is the problem since I would think throttling is reducing... with my app it went from them being delivered consistently to none at all. But here is the response I got from Apple. I'll post the next email I get from them. The behavior you are seeing is expected, and it is due to content-available (aka "background" or "silent") push notifications being throttled when being delivered to apps that are in the background. Background push notifications are never guaranteed to be delivered to the app every single time. Notifications sent at low priority (priority 5) are throttled, regardless of payload. Background push notifications are always sent at low priority. Although you may expect up to several background push notifications per hour across all apps on a device, it is entirely possible and appropriate that you may receive none at all. The purpose of the throttle is to allow background activity for an app in a resource-efficient manner. It also serves to prevent apps from consuming too much of the user’s battery or cellular data with background traffic.  Once the device-wide battery or data budgets have been exhausted, no more background push notifications will be delivered until the budgets are reset. The budgets are reset every 24 hours, and this schedule cannot be changed by user or developer action.  Additionally, these notifications will not be delivered to the app at all if the user has not launched the app for a while. The throttle is disabled if you run your app with a debugger attached. This allows you to test that your notifications are being received correctly, but should only be considered a best-case scenario.  The important point is that apps should never be designed expecting that every push notification will be received. This is not how APNs is intended to work; it is intended to inform the user or app that some event of interest has occurred. Apps are expected to work properly, albeit perhaps with degraded functionality, if push notifications are not received. The user can turn off push notifications or background app updates at any time, and of course push notifications will not be received if the device doesn’t have network connectivity. Also, an app will not be woken in the background by a push notification if the app had previously been force-quit. Force quit is considered a drastic choice by the user to say that they do not want the app to run, often because it misbehaved in some unrecoverable manner.  The WWDC 2020 video "Background execution demystified" (https://developer.apple.com/videos/play/wwdc2020/10063/) explains the factors that effect background runtime. I suggest looking into using a Notification Service Extension as discussed at (I deleted the URL because, funny as it is, I got an error saying the domain "developer.apple.com'" is not allowed on this forum :) ) The Notification Service Extension will be executed for every visible push notification. So, it could serve your needs, as long as the user has not disabled the visibility of your notifications through various settings. The service extension will not be executed for push notifications that will not be presented visually. Although using totally silent pushes will not be a feasible solution for most apps, in iOS 15 and above, you may want to look at using the Interruption Levels for notifications and setting your notifications to "passive". This setting will allow you to send high priority pushes, and execute the Notification Service Extension when the notification arrives, but will be less likely to interrupt the user, although these are not completely invisible like silent pushes. WWDC 2021 video "Send communication and Time Sensitive notifications" (https://developer.apple.com/videos/play/wwdc2021/10091/) explains the Interruption Levels introduced in iOS 15.

From the last response from Apple "...there has been some changes to the throttling algorithm on iOS 15 that made it stricter. There has been some relaxing of the throttling on 15.4, so you might see better results if you test it with the latest beta. But there will be throttling one way or another without a NSE."

"And the way it was resolved was by opening the "Activity Monitor" app and under CPU, when I sort by most used process, "installd" was the one I stop/kill and after that, the xcode app restart the download and completed successfully." This worked for me... thanks!

Doesn't anyone know how to use this method? :)