I started having the same issue recently and noticed the pumps had a new form of vapor cap/sealer on the end of the nozzle....I now pump gas with two hands, one holding pump and the other pulling that vapor guard back...fills up full every time

 

So, went off on a 300 mi drive yesterday. "Filled" up locally at the start with gauge showing 1/2 tank. Gauge showed about 7/8 when the hose stopped, and could not put anymore in. Filled up on the way back in, and the gauge showed full this time. Maybe it is just the hoses, but, as I said, I had the problem at several different stations. Oh, well.