It’s no biggy but on the Home page I’ve lost Home Theater 4.0 and now have two buttons for Settings. I’ve added the HT 4.0 button on the bottom row but I was already getting used to it at the top.
I think that the interface differs on the Z9x to that on the Z1000 Pro so can't really comment on the location of the buttons on the home screen. They are normally all along the bottom row on the Z1000 Pro.
Things don't sound right though? No idea as to why the buttons would be dissappearing and can only assume you've a glitch with the software?. Have you updated the firmware yet?