This may be more of an Android issue than a Samsung/Note 8 one, but I'm growing frustrated with a notification issue.
I have a Note 8 and an iPhone 8 Plus - the latter of which receives all notifications as expected on Facebook, Twitter, Messenger, WhatsApp etc. On my Note 8 though, these either arrive late - or not at all, even if I have the apps open and active, running in the background, screen off or on, whether on Wifi or mobile network.
As a test right now, I've received a tweet - my iPhone notified me immediately, but even 5 min later still nothing on my Note 8. On WhatsApp though, I did receive the notification - almost immediately the same time as the iPhone. I'm on the latest update available, stock OS, and tried a factory reset already.