Try these steps
1) go to network settings and go offline
2) go to settings > All Settings > System > Storage > Manage Storage > view contents >select minecraft (button with 3 lines) > manage game > saved data > delete from console. (It is still on the server, so you can get it back)
3) hold xbox button for 10 seconds to shut it down
4) wait 30 seconds, then turn it back on
5) go back online in settings
6) launch minecraft
7) go to world 1, click A, sync it, then click B to go back to your world menu. Go through and sync all worlds. Do NOT load them, just sync.
8) once all worlds are sync'd, quit minecraft (home button, button with 3 lines, quit
9) restart minecraft
Hope it works!