If you compete the quest I Fought the Law and side with the NCR and clean out the prison, the radio always says the NCR failed as does the ending of the game. Lieutenant Hayes seems to prematurely leave for Camp Forlorn Hope before getting the chance to talk to him which may be the cause of this bug.
Since it looks like the staff are reading/posting on here a lot lately, I might as well ask if this is being fixed in the next patch?