Had this charging issue with Nougat update on G S6. Fast charge is turned on but not functioning. Called At&t, Samsung, Google, then Samsung again. No help. I even did a factory reset. Went to Best Buy to have them "flash " the software on to the phone assuming it was buggy. They can't. The Samsung reps don't have the S6 version available. This is not isolated to a few s6's, and Samsung seems to know it's an issue but not motivated to fix it. I might even assume it was intentional to force us to upgrade to S8.