[Q] Strange issue when updating past 4.1.2 topic

HI there,

My first post and its a question! i'll just begin shall i?

I am currently on 4.1.2 and all is well in terms of everything is working as intended. But when I decided to move up to another firmware such as KitKat or even Lollipop, my phone begins to give off somewhat of a radiation which I feel in my hands! Its quite uncomfortable which forces me back to 4.1.2.

I moved up to:
Firmware: Lollipop 5.0.2 by Cynogenmod Build 14
Baseband Version: i9100XXMS2
Kernel: 3.0.64-CM

Irregardless of what firmware I upgrade to, if its anything higher than 4.1.2, I have this strange issue of radiation which I can feel. Any ideas?
Modem issue? Phone issue? Me being the issue?

Thanks