In most US states, there were laws (anti-gambling laws mostly) which prevented decisions given in boxing contests going full distance (called no-decision bouts).
While historically such fights have been recorded as "newspaper decisions" ie. the winner has been listed as reported by a consensus decision of reporters witnessing the bout (and you can see Greb's record littered with W-NWS markings), those bouts are not accounted in official career record. After all - officially there was no verdict nor winner.