DIAGNOSIS Yes, this is normal operation. The condenser coils are built into the cabinet walls. Heat from the refrigerant is rejected through these sides and back.
FIX This is not a problem to fix. Ensure the unit has proper ventilation. There must be at least 2 inches of clearance from the wall and sides. Do not build it into an enclosure without adequate airflow. The heat needs to dissipate.
IF THAT DIDN'T WORK If the sides become too hot to touch for more than a few seconds, or if cooling performance is poor, the system may be overcharged or the condenser is dirty. This is rare from the factory.
HEADS UP Never cover the top grille or side vents. Blocking airflow causes the compressor to overheat and fail prematurely. The hot exterior is how it works.