Why some apps not showing notifications or listed under Notifications+Actions?

[wilsey]

I don't receive any notifications at all from these 3 apps: BBM Beta, 6tag and Path. For BBM Beta and 6tag, it happened right after upgraded to Lumia Cyan.
For 6tag and Path, it will occasionally show the notifications on the Live Tile. However, for BBM Beta, it doesn't show anything at all.

 

[Loco5150]

At least in 6tag you need to go in to settings and enable background agent.

 

[wilsey]

At least in 6tag you need to go in to settings and enable background agent.

Yeap, I have always enabled the background agent in 6tag. Only after upgraded to Cyan, the problems arise. After the Cyan update, only the official Instagram app that always gives consistent notifications. Before Cyan, both 6tag and Instagram will give notifications.
But, what really puzzled me, is that, even the Windows Phone Helps unable to solve this.
I believe I don't get the notifications is because the apps are not listed under Notifications+Actions