I could not guess from what you giving of info what could have happend
But if it was a system update then the old one worked better for you
If you changed the wall charger socket .. so you pluged in your charger
in different socket it can make a change to
Sometimes the charger gets hot in some sockets in other it does not even get warm
So, the wall socket is important too .. where you charge it..
If you changed the original charger.. yeah..it can get worse but also it can get better..
And sometimes also the cable..some stock cable are sometimes worse then evan the
cheap eBay one.. I have had some experiance that some cheap ebay cable gave me the best Volt charge for my phones
So, you need to look now what could it be..
Hope I have helped
But maybe it will get better with some update again..or get worse..or stay same..
You need to test it more in different situations
