Oh thank God I'm not alone, I thought for the longest time I was the only one who was having this problem because I couldn't find anyone else on any forms talking about it. After purchasing my Note 3 I had this problem and even un-rooted it and went back and had my phone replaced to fix it. And I thought it had untill I started using my wifi again and after playing around for a little while I quickly realized that all the problems were directly linked to using the wifi.So the next day I took the phone back in and after me and an employee experiment with it for a little while we came up with a solution, we discovered that if you leave the 4G on and then turn on the WiFi (NEVER EVER let the wifi be active without the 4G being active first, even for a second) that it works without any problems whatsoever and after using this method for several months now I can report that there are no longer any problems with my Note 3. However I am NOT a huge fan of the solution since anytime your phone cannot connect to wifi for whatever reason the automatically connect to 4G and I've noticed my data usage has gone up as a result. This seems like a HUGE oversight on someone's part at Samsung, I really wish they would fix this. Now I have noticed a couple days ago that I am able to use my wifi only without having any of the problems EXCEPT for the battery drain one. Hope this helps and please let me know if it does, good luck.