If you are rooted try the COMPLETE unrooting procedure mentioned at various places by flashing the latest stock firmware available from sammobile. This is to make sure your device software is like brand new. Test it for at least a day. Do a mega wipe (erasing everything even on internal SD card) before which can fix it in some cases.
When rooting again make sure you have the most bug free version of the recovery. CWM 126.96.36.199 is known to have minor problems here and there but nothing concerning to this topic.