I had the same problem a couple of years after I began driving my new 2018 RAM 1500. I eventually took it to the dealer and they said it was the vent valve and replaced the entire tank. 4 months ago (140K miles), the problem came back. I found a YT video on this forum where the guy said to run a 3/8”-1/2” hydraulic hose down to the rollover valve on top of the tank to unstick the valve. I only got the hose 1/2 way down the fill neck and hit something hard, maybe the evap air filter? I ran the hose in 6-8 time and hit the same obstruction. Whatever it did worked because I’ve had no fueling issues since. Maybe someone on the forum can tell is what is in the line between the tank and the fill tube?