Having the same problem with battery on the iPhone 8 and since the software update my phone is glitching and freezing and being unresponsive! The fact my battery literally drops from 30% to 2% in 10 mins is ridiculous it’s not even consistent sometimes it lasts for nearly the day other days I have to charge it 3/4 times and when charging it’s charging so fast as well but then dropping! For the price of Apple you expect so much more ! Even the newer models have the problem sort it out apple !