My previous batteries showed 100% in Battery health. Both were actually faulty and showing the same or less than the suggested mAh in coconut battery. I had the same problems after updates. It can't be the battery, surely? Well, I tested it with coconut battery and the mAh for one battery was exactly the right amount (faulty and battery swelled) and the other was much lower by about 400 mAh (faulty). If it's close to what it should be, great! If not, the battery may be faulty.
That's the only way to tell, other than swap the battery for one that you know is good.