It's inherent to almost any Samsung phone. My SII did it. My S4 did it. My Note 3 does it.
It has to do with the proximity sensor changing too quickly.
I'm an Air cooling Editor, and News Editor, as well as moderator at Overclock.net. I plan to bring here, what we over there call a professional initiative. My news duties consist of reviewing deciding what constitutes as valid information, and if it is indeed "news". For air cooling, I simply moderate the air cooling thread. So desktop cooling, and news. I'll be glad to assist in any way I can.