Yes, it is normal.

That message is just an alert that indicates that the dive computer has cleaned the saturation of the tissues.
Before an update all the tissue saturation data of the dive computer are cleared in order to perform a clean update of the OS

It is a warning that can be ignored if your tissues have no saturation (you made no dives in the previous 48hrs)
The red "Tissue Reset" alert in the main screen will disappear after the next dive or after 48hrs.
                          
For more info refer to "Reset to default" and "after a Tissue Reset" in the User Manual