HELP! Samsung galaxy s4 i9505 4.4.2 ROOTED RANDOMLY REBOOTS topic

Im new to rooting and stuff so please explain things in detail. I have samsung galaxy s4 i9505 on android 4.4.2 XXUGNG8. I rooted it yesterday using cf autoroot. I had to disable knox because of supersu. I also removed youtube.apk which was a system app so i could install another YouTube apk which had more features. Everything seemed to be working well untill i pressed the power button to just switch off the screen and then my phone just went to the samsung rebooting screen. The song didn't play and the screen that says samsung galaxy s4 gti9505 never came up. Just the screen saying samsung. Then it went to my lockscreen. The reboot is like a quick reboot. It doesnt take as long as a normal reboot. This doesn't always happen. It had happened 5 or 6 times since last night when i press the power button. However its annoying. It also happened after someone called my phone. After i finished and they put the phone down it just rebooted again.

Please can someone help me? Someone else already said to flash the latest firmware for my device. But will that remove the root? Also, i cant find the right version. For my phone the:
AP: I9505XXUGNG8
CP: I9505XXUGNG8
CSC:I9505BTUGNG2

Please can someone help asap. Thanks.

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