Had a new RV neighbor park next door and happened to notice one time when he just normally closed his door, that when he went to go back inside, the door wouldn't open. He had to knock and get his wife to open the door. I had a similar problem with my '94 Bounder and his is a '16 Winnie Vista.
Talking to him, seems as though they've had nothing but trouble with the RV, and the lock is just one thing out of many. They've had to have the wife climb in a window twice to open the door. I tested the lower lock and the spring seemed a bit weak to me.
Their lock assembly looks very similar to the one my '02 Journey, and much like the one on my '94 Bounder...so the same door handle and lock assembly manufacturer no doubt. With the same strengths & weaknesses.
I thought I had a permanent work around for them and installed it. So far it's working great, it's the same fix I used on my '94 Bounder and my '02 Journey and is simply a zip tie around the latching lever and the door handle. That means you use the upper dead bolt exclusively, but that lock is much less susceptible to being accidently locked. Seems as though the lower latch spring either comes weak from the manufacturer, or gets weak from usage, or breaks. This allows a door slam, doesn't even have to be a strong one, to partially lock the door, and yanking on the outside door handle doesn't open it.
I found if I added this zip tie, I never had to worry about that particular problem, and that's over 12 years of use.
It's a simple fix, costs next to nothing, and IMO, has little to no effect on security because having both locks locked wouldn't slow a determined thief down much at all considering all the windows a RV has. And it offsets the expense and anxiety when you get locked out simply from closing the door.
So if you find yourself locked out of your RV occasionally, you might consider doing this workaround to save a bit of sanity.
See the entire story here if you're interested in a longer write up with additional pictures: Self locking door latch work around...