I can beat that, my reserve goalkeeper has scored 8 goals and has 2 assists in only 5 games, also has an average rating of 9.5 when he's a 5 1 4 2, he must be a genius! In my case it's obviously a teamsheet error.
If you look, it only happens to players who have the same name as an outfield player. The engine sometimes picks the goalkeeper to get the stat instead of the outfield player if they both played in the same match.
In my case the GK'S name is miguel and i have no other players with that name, the closest would be Arteta's first name (Mikel) otherwise there are no similarities. Is it just an error?