The mechanism in the pump depends on a free flowing, successfully venting filler neck. If a bit of detritus got into yours and is reducing the flow, it will do exactly that. Seems more likely than that every pump handle you visit is defective...either that or the small gas tank/bladder on your Prius can't accept a high enough flow rate to work with normal pumps, though I'd be surprised if Toyota missed that.

Dropping the tank and replacing it or the filler neck is a pretty easy DIY project.

Um, no.

This also illuminated the SES light and, more importantly, would have resulted in a failed emissions test. Instead of spending $250 on a new one I hit the old canister with a hammer to break up the charcoal and it was all good.

Edit: Service Engine Soon

The hammer idea is new to me. I spent several years working on cars and still like to wrench on the side.

It seemed to me that sometimes the angles would mean the gas splashed off the filler tube in the wrong way and confused the dispenser. There's a bunch of different ways to run a filler tube, and different dispenser handles, so I adapt.

In my case, my first vehicle was older than me, so you don't exactly complain to the manufacturer that it has trouble filling at some stations. When newer vehicles acted the same way, I already knew how to jiggle the handle to fill up, so I just wouldn't get to wash my windows at the same time as I filled up, if I went to the wrong station. I wasn't ever one to buy stuff inside while the vehicle was filling, so not a big loss of functionality.