[OnePlus 2 Q&A, Help & Troubleshooting] vonotny:
Hi everyone,

I've been having a very strange problem for a couple of days now. Whenever my phone's screen is off and the phone has been idle for some time, I don't receive notifications anymore. Facebook notifications don't work at all, no matter whether the phone is active or not, but I also don't get FB Messenger and WhatsApp notifications. Sometimes they come through as soon as I turn on the screen, and sometimes I only see them when I open the respective app. I didn't mess with app permissions, and I also have set each app to "important" in the notification settings. It also doesn't seem to matter whether I'm on WiFi or on mobile data.

Gmail, SMS and calls don't seem to be a problem, although I sometimes have a feeling that emails come through to my phone with a considerable delay, as compared to my Gmail inbox on my computer.

The strange thing is, when I had the phone all new, everything worked as it should and I received ALL notifications from EVERY app IMMEDIATELY when they came in. This issue with notifications no longer coming through started occurring a couple days ago after I had first flashed the Boeffla Kernel (though I'm not sure if it has anything to do with that.) So I went back to the stock kernel, but the problem was still there. Then I re-flashed my original Nandroid backup from when I had first flashed TWRP, in order to set the system back to "stock", wiped data and cache, re-installed every app (the critical ones, i.e. Facebook, Messenger and WhatsApp, via Play Store, and the non-critical ones via Titanium Backup), and the problem is still there. I've done this three times now, to no avail.

My phone is rooted and I have Xposed installed, I'm using SuperSU and a number of root apps such as 3c Toolbox, Le DPI Changer and Font Installer. 3c Toolbox is set to clear caches on every reboot. As for Xposed, I use only VibrateMode to change the notification slider from all/important/none to all/vibrate/none, and GravityBox to center the clock in the status bar and to set the volume buttons to skip tracks on long press. I also have Glimpse Notifications installed so that the screen lights up when a notification comes in.

The funny thing is, notifications not coming through is one of the reasons I switched to the OPT from the Huawei Mate 7, where this issue was due to power management settings by Huawei. Since I'm now back on the stock kernel and have also no power saving apps such as Greenify or Amplify enabled, I am really out of ideas as to why this happens. The next step is to flash a fully stock OOS 2.1.2 (my Nandroid backup is already rooted and with my Google account set up), wipe data and cache, and re-install every app again.

Does anyone here have any idea what the problem (and the solution to it) might be?

UPDATE: After I wrote the last sentence, I received two messages simultaneously, one from Messenger and one from WhatsApp. I was at home and on WiFi, and both coming in at the same time must mean that the phone receives push notifications in fixed intervals, since the sender of both messages was the same person and sent them consecutively, i.e. with at least a minute in-between. Now I am especially confused since a) they came through at all, even though the screen was off and the phone had been idle for at least 15 minutes, and b) they came through at the same time, which was definitely not the time when they had been sent.

The confusion is complete now ... any input is appreciated. Thanks in advance!