Weird Galaxy S6 behavior

[AC Question]

Hey everyone, got the Marshmallow update last week and everything's been fine, except for one thing. Randomly, while my phone is in sleep mode, I lose 10% battery. For 2-3 hours, I could be on 80% (for example), then I randomly drop to 72%. According to GSAM, my battery is draining due to my wifi connection. So I went to the my settings and made it so the wifi turns off while the screen is off but unfortunately for me, this doesn't do anything. While the phone is sleeping, the wifi is still on (I even unchecked the option where the phone notifies you when you're near an open wifi signal). What should I do?

 

[Rukbat]

Marshmallow has a known wifi issue (among many other issues). Wait for the update.