Anyone having trouble with maintaining a stable screen brightness level? I have the 6s plus and in the previous versions of IOS 11 my screen constantly changed brightness. I can set it at a particular level, lock my phone then open it a few minutes later and it is at a different level. Sometimes when I slide up the control centre I can see the brightness level actually sliding up or down without me touching it. Sometimes it also changes while using the phone too.I thought after updating to IOS 12 it might be better but as yet -same issue. I can never get a stable constant level of brightness. Any thoughts? Thanks.