Arrow [Q] Push Notifications Delayed/ Undelivered[EXCEPT GMAIL]

Hi everybody,

My device is rooted with pure stock 4.2.2 and mediatek 6572 processor.

Problems: (ONLY OVER WIFI and SCREEN OFF)

1. all my notifications are either delayed or undelivered, when screen is off.(not SMSes but those over WiFi)
2. GTalk messages always take 5 minutes(Heartbeat Interval duration) when screen off
3. Play Store apps are never updated/ downloaded when screen is off, start right after screen is on
4. IM apps like Xabber never get IMs until screen turned on

Exceptions:
1. NO PROBLEMS WHILE SCREEN ON
2. Gmail ALWAYS gets email exactly after 30 seconds or more(possibly rules out connection timing out)
3. Above problems disappear using MOBILE DATA
4. NEVER HAPPENS during charging
5. With LOCATION REPORTING enabled, Talk messages reach within 30-40 seconds, with screen off.( battery consumption doubles also)

ALREADY TRIED:-
1. In sleep policy set to Always On
2. Used PNF and set heartbeat interval at 5 minutes, to no avail
3. PORT 5228 not blocked on router
4. WiFi optimizations turned off
5. No battery saving mode or 3rd party app enabled
6. Background Data Restrictions disabled
7. Same thing in SAFE MODE
8. Did FACTORY RESET
9. Tried logging in from another Google account

Any help is greatly appreciated!!