More Galaxy A3 (2016) users who upgraded their handsets to Android 7.0 have been complaining that they cannot load the battery more than 87 percent. Even worse, it looks like none of the usual bug-fixing methods works.
https://www.notebookcheck.net/Samsung-Galaxy-A3-2016-with-Nougat-plagued-by-charging-bug.249904.0.html