I don't have a 5th wheel but I've seen lots of damage caused by "them" - which is usually oversight on the owner's part. My friend is on his 2nd season with his new 5th after having class As. He was unhitching and I went over to help because he was having an issue unlatching. He then lubed the hitch and did some other things and shut the tailgate. I was visiting and looked around and he had gotten in the truck to just pull it away from the trailer - but his tailgate was up and the pin on the trailer was about 6" and closing on the top of the tailgate. I started hollering along with his wife who saw the situation as well. He stopped about an inch from the tailgate. If we hadn't been there it would have been another one of those "bowed" tailgates you see from time to time.
All that to say that I don't think it is a "sign of bad luck with that RV", it's just getting familiar with it and the processes involved. The more you use it the more familiar you will get.....just remember to CLOSE that tailgate and keep an eye on it in the rear view mirror!!