It’s weird that the notification backdoor never gets talked about, but your Whatsapp messages are decrypted in plain sight when the text content is shipped through the notification services. This is mentioned always for Signal but Whatsapp always gets a pass even though it’s a way more malicious company and indeed probably using that hole to profile/track it’s users.

The only response is “oh no Whatsapp cant leak anything the security model of how chat messages are backed up is a-okay!”

Signal got called out for it because it actually happened to a user with the police. Of course it affects all apps. It's also local, so irrelevant to the discussion of networked/encryption hacks someone alleged above.