Hello to all, FP2 with FP Open installed, same symptoms described by the OP with or without root/XPosed/FakeGapps. Went crazy during the weekend, because battery was charging perfectly just two days ago. Behavior became suddenly erratic, switching from charging to not charging and having sudden fake or real fast discharges. Checked for apps, none using too much CPU or related to the problem. Cleaned contacts and battery. Tried all the solutions in the battery guide, none helped. Realized then that charging was stable with a bad USB cable that I was going to throw away this weekend, one that didn’t allow for syncing. Then noticed that changing the USB configuration in developer options stabilized charging while the setting didn’t revert to its default (“charging”). Finally pinned down the problem: USB debugging needs to be turned on always for charging to be rock solid! I suppose there’s some bug in the OS that creates instability in the charging circuit once USB debugging is turned off. Phone is perfect again. Hope this helps other people having the same problem.