Fuel pushing out filler tube

I can think of one situation, this deal is troubling.

"Let's say" the filler tube is for some reason extended further than "would expect" into the tank. This produces a dome so to say in the tank, because any fuel/ air / vapor above the entrance of the filler tube becomes a "pressure dome." Perhaps this is happening, and warming of the fuel both from temp and from "action" (energy imparted by the pump) causes that fuel to want to expand. It's only point of release is to expand up into the filler tube.

What SHOULD be happening is that if this is the case, the fuel backing up into the filler should be spilling out the vent tube.

The fuel cap should NOT be vented