Samsung Galaxy Note 2 — Wifi issues : Note 2 on Team UB ROM Lollipop 5.1

I used to have the DN4 ROM working flawlessly on my N7100. The DN4 ROM was 4.4 Jellybean.

Then I started facing Wifi issues all of a sudden like below:
WiFi button freezing

Restarting the phone would generally solve the issue, but then it rarely worked.

I flashed the Team UB ROM which is Lollipop 5.1. I have TWRP installed with 2.8.7.0.

It was a clean flash, including data wipe.

The issues still persists.
-Wifi button is grayed out.
-It Turns on/off but can't find any Wifi routers.
-It finds the network but doesn't connect.

Removing the battery, pressing the power button for sometime, restarting the phone in recovery mode, clearing the cache and dalvik cache.

Doing the above sometimes, solves the problem but not always, and all of a sudden phone loses the connection and I have to repeat the above steps all over AGAIN.

Please help if anyone has faced similar issues.

— modified on Jul 1, 2015, 8:59:37 PM