[AC Question]

I updated the phone to Marshmellow 6.0.1

Now the phone skips back screen like I have pressed the back button without me touching the phone.
If I am in an app/game it keeps trying to close it.
If I am using anything it tries to skip back to the previous screen

I have wiped the cache partition - no impact
I have backed up and done a hard factory reset - trying to set-up the phone and it has skipped back to welcome page so that hasn't worked.

Any suggestions or is my 4 month old Samsung Galaxy S6 now about as useful as a brick as I can't use it!

Any suggestions?