I also wonder what type of Jack it is. Not common, but I've heard stories about dealers putting jacks on that can barely accommodate the weight of the trailer dry.
There's also a chance that it was bent. If it's slightly bent, it can cause too much friction and make the motor work too hard.
The other common problem is the jack being extended or lowered and not stopping the motor when it bottoms out. Although, that's not usually an issue on new trailers. Unless this thing had been moved on the lot frequently by an inexperienced person.