I had heard a few years ago (his first or 2nd season in Nashville) that Josi didn't like him for whatever reason. He's always been a pretty brash type player. He was once suspended by the AHL for flipping off the opposing bench after scoring a goal. (It was Milwaukee public schools' yearly field trip to the hockey game).
Kevin Fiala Suspended Two-Games by the AHL
He got in a scrap with Arvidsson at practice a few weeks ago.
Other than those two instances it's all a bunch of hearsay. He's a young talented hockey player. He's not the first one to piss off his older teammates by being overly cocky.