OK I found how to trigger it is quite simple it is due to rotating the phone
Device mako
Channel rc proposed bq channels r444
how to reproduce from a fresh boot
Login to your phone
Put yourself in portrait mode
open the dash on the time and date
rotate to landscape = the dash does not rotate
close the dash = unity 8 rotate to landscape
Rotate to portrait = unity8 rotate to portrait
Open the dash on time and date = calendar disappeared
OK I found how to trigger it is quite simple it is due to rotating the phone
Device mako
Channel rc proposed bq channels r444
how to reproduce from a fresh boot
Login to your phone
Put yourself in portrait mode
open the dash on the time and date
rotate to landscape = the dash does not rotate
close the dash = unity 8 rotate to landscape
Rotate to portrait = unity8 rotate to portrait
Open the dash on time and date = calendar disappeared