Or Instagram belonging to Facebook? They already know.

I think the point is they get to know the exact time you first see the notification. It's a massive flaw in the OS, and I believe I have read about this years ago already, so that "privacy OS" is not intending to fix this leak

Push notifications go through Apple servers.

HTTP GET request comes from the device loading the image; AFAIK though wouldn’t be a big deal if Apple’s servers loaded and cached it.

So Meta can watch for the GET requests and determine:

• time of delivery to device
• approximate location of the device
• device’s IP, used to correlate other activity done on that device gathered elsewhere by the IG/FB tracking network

And derive:

• what kind of connection you are using
• from where
• when
• what time of day and location do you most often read IG
• optimal time to try and distract you
• who your preferred service carriers are and if/when you change them
• how often you deviate from this pattern
• through correlation, determine what deviation might be significant based on other data collected from your device or nearby devices at the same time
• oh wow so and so didn’t look at IG much because they searched for baby clothes are they pregnant? Is a friend? Can we show more ads based on that angle to get sales?
• and other, much more devious, much grosser intrusions
• they get more sales from oblivious users
• they grow their panopticon