Having the same issue on a S5. I understand it effects several of the Samsung models and T-Mobile is aware. Surprised not reading much here. I also had a greatly increased battery drain with WiFi apparently trying to reset or update my 911 information. Once they (customer service) reset my E911 info, the battery was better - but not turning wifi caling back on until a fix is out. I'm guessing they may not waste time fixing 5.0.1 and instead roll the fix out with 5.1.1 While two month with a problem that many went to T-Mobile to so they could have wifi calling - I find it rather amazing than many more are not complaining including Android Central running story on it. However on the other side, apparently T-Mobile's coverage is much better than years ago because there is less complaining. But I for one wish it would get fixed.