I have a tandem axle trailer and when it's parked at home I have one tire on one side (tire toward the front of the trailer) raised to level the trailer. So far (five years) there have been no issues I've observed (suspension issues, uneven tire wear, pulling to one side while towing, etc.) and I doubt this would cause any damage given the trailer is stationary and not subjected to any real shock or excessive loads when parked.