I’m afraid this sounds very much like a faulty battery. Report all the details to iFixit and request a replacement. You’ll find [https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjr8v2KoLjlAhUBnVwKHU_lB8UQFjAAegQIARAB&url=https%3A%2F%2Fwww.nirsoft.net%2Futils%2Fbattery_information_view.html&usg=AOvVaw3zie6CcIk332E6r6_2PWzu|BatteryInfoView] from Nirsoft is a great utility for reporting battery state.