Galaxy S5: Apps are stopping often

[DarkUltra]

Hi

I have several apps that stop every now and then. I have done a factory data reset recently and it is still happening. I also have some corrupt graphics in Mangareader every now and then. Could this be a hardware issue or should I reset the phone again? I have not rooted the phone.

Apps installed:
1Weather
500px
Allshare Cast Dongle
BubbleUPnP
GO Keyboard
SyncMe
etc

Specs:
SM-G900F
4.4.2
G900FXXU1ANCE
3.4.0-1182732
dpi@SWDD5815 #1
Mon Mar 31 12:21:23 KST 2014
KOT49H.G900FXXU1ANCE
Enforcing
SEPF_SM-G900F_4.4.2_0015
MDF v1.0 Release 2
VPN v1.4 Release 1