Can rough roads create a suction from the water tank vent?

We had a 2000 Holiday Rambler; Aluma-lite that would drain 3/4 of the water out via the overflow tube. The tube was installed into the tank within 3" of the bottom. Once you got the siphon started she would run down until it sucked air. Several times we left home with a full tank and got to the campsite with a quarter tank left.

I fixed it by getting rid of that pile of junk.