This is actually completely normal. Check out the picture of the real life AirAsia A320 below:
The reason for this is explained in this article linked below:
Basically, long story short… it is to represent the flag blowing in the wind. A flag that is blowing in the wind can appear backwards, and therefore flags from some countries are placed on aircraft backwards to represent the wind direction/direction of travel, which is the case above. It also represents a moving vessel and in this case an aircraft.
Hope this helps explain!