Huh, that random rectangle in the middle of a TV studio is a weird one. But looking at other official maps, like https://data.lacity.org/City-Infrastructure-Service-Requests/City-Boundary-of-Los-Angeles/ppge-zfr4, it seems real! I guess it's just one parcel that never got annexed for some reason, though I wasn't able to find any specific information about it anywhere. It should probably be an "inner" member of the Los Angeles city relation.