Eagle cost himself a stroke when he didn't read the caddie book properly on hole 8 at Vista. He went OB on his drive, re-tee, OB again, re-tee, drive to 50', miss putt, tap in for a 6. The caddie book says that after his second OB he could have gone to the drop zone, where he probably would have saved himself a long putt. Could have been a 5 if he was prepared.
He didn't miss the putt from 50', he made it for six. Tee shot + OB penalty + Re-throw + OB penalty + Re-throw + Putt = 6. Considering the drop zone is definitely further away than where he hit that 50 footer, I don't think we can assume he makes his shot from the DZ, which is the only way he could have saved himself a throw there. By making the putt for six, he made any debate about the merits of the DZ moot.