hey guys i got a question for you my friend has a iphone 5s and when he updated to ios 12 he has been having random shutdowns around 50 to 60% of battery, and also sometimes once it hits 60% to goes directly to 14% and then dies. When he plugs the phone in it jumps back to what percent it died at. If someone could help I would really appreciate it alot. Please write back. Thanks.