The result I had when mine was stuck shut was it was extremely hard to get fuel to go in at all, not because it was coming up the filler tube, but that the vapors in the tank had no where to go but out the filler tube, which made the gas nozzle impossible to get to flow at any reasonable speed (would kick off immediately), so the process of filling was extremely slow and frustrating.
It did set a code, which I never had read, I knew where the problem was and that it had stuck shut instead of open.
On the last refuel of that trip it was open, refuel was normal. Let me to believe that the valve was stuck closed then either freed itself and was operating normally or had went from stuck closed to stuck open. At any rate I replaced it, that was the last time because THEN I heard not to add any fuel after the nozzle clicks off and haven't had a failure since then, maybe 4 years ago.
I only remember a couple times when I had splashback and was very minor and was when I would top off the tank.
From my experience I don't think it's the valve.