i wonder is that issues means you have a faulty device coz i have it on my S4.
nung hindi ko pa ina-update very annoying after the update meron pa rin but not as grabe nung previous.
So my million dollar question:
do i have a faulty device?
As i've checked the net for this concern. There is a lot of S4 users encountering the problem.
I think the problem is in the software side of the S4. Since you've said before that it was in someway lessen when you updated your OS. You can try as well the link I provided below if it will resolve it completely.
And let us wait as well for the release of the newest OS update:
Hope this helps,