Hey nice script but you need it to be like below or it will not unset people reason for away

alias return {
  nick %orignick
  amsg 14,1[0,1 I have returned at:3,1 $time(hh:nntt) 14,1][0,1 From:3,1 %away.reason 14,1]
  unset %orignick
  unset %away.reason
  unset %away.time
  away
} 

Also if you wanted it in text commands you could use this

on *:TEXT:!away*:#: {
    set %away.time $time(hh:nntt)
    set %orignick $me
    nick (nick)
    set %away.reason $2-
    amsg 4[ $nick is now away! ]12[ Reason: %away.reason ]
    away %away.reason
  }
}
on *:TEXT:!back*:#: {
    nick %orignick
    amsg 4[ $nick has returned at: $time(hh:nntt) ]12[ From: %away.reason ]
    unset %orignick
    unset %away.reason
    unset %away.time
    away
  }
}