https://apolloinrealtime.org/11/?t=022:07:04&ch=50A computer goes down and they have to restore to a backup from a checkpoint 40 minutes earlier, meaning that 40 minutes of data is lost. A bit of banter ensues with Flight Director Glynn Lunney telling FIDO Jay Greene that "you took [the checkpoint] in the wrong place!" Discussion continues until 022:10:00 or so.
Earlier in the shift, he'd been questioning Greene on the reasons for needing to take checkpoints:
https://apolloinrealtime.org/11/?t=019:56:49&ch=20However, as Greene says to his backroom later, the real incident provided the best illustration of why checkpoints are needed. "We scored on the flight director... it's better than any words of explanation."
https://apolloinrealtime.org/11/?t=022:13:21&ch=20