I get a message on Desktop and read it. Around 20 seconds later I’ll get a notification for the message on my Pixel, and then it’ll disappear (since of course, it has already been read). But the general issue it’s that messages take so long to generate notifications.
The funny part: Delivery is instant 
but the notification can take up to 40 seconds to show up at times, other times it’ll take 2 seconds.
For example see the message located here:
1699260349502
