Absolutely true!! There is NO WAY a 1/4" vent line is going to allow the tank to fill. This issue is IN THE FILLER somehow. Gasket below is deteriorated hanging down, some obstruction, rusted partially caved in, whatever
In some cases it's the station/ nozzle. There's two stations here that run ridiculously high line pressures. Hell you can feel it when the nozzle shuts off. I don't go to them unless "I forget" Both of them slop fuel all over the place and shut off prematurely