Sadly, I’ve had this issue and it’s still an on going one. I keep saving my clock as London (UK) time and it always changes to CUP when my phone has been turned off and back on. It’s starting to get annoying as it seems my phone always has a problem with every update, like how my phone no longer wants to charge unless I turn it off and back on, never had this problem up until they recently started throwing all the updates in every week.