I find this is a problem on our 2015 Vista 31 foot. It happens as we gpo across dips like at driveways, etc. and does it with the doors locked or not. Apparently the frame twists enough to move the latch and open? Sounds bad for the rest of the unit, right?
But it does it and the latches appear to be good, so I've moved on to other solutions. Step one is to locate a metal part just inside the door, drill a hole and add a bungee to act as a backup for when the latch fails! With a small diameter bungee about 6 inches long, I can hook it to the door and frame by stretching it a bit and then when the latch fails, the bungee keeps the door from swinging out in traffic! Not a good solution but better than folks flagging me down to close the door.
At campgrounds we leave the cord off but make it part of teardown to make sure they are all in place again.