I’ve been getting lessons in the importance of calm patience from various sources. For instance, when I realized that Windows Backup would require too much effort to function as it should, I expanded my Linux backup partition to fill the entire backup drive, with the intent of adding Windows directories to the backup. To do this, as Truecrypt volumes have no official expansion capability, I moved the backups to my home folder, wiped the partitions, created a new LUKS volume, and moved the backups back. The partition operations were insanely easy with Red Hat’s Palimpsest. I put them in the root of the drive, and Deja Dup kept failing a CRC check and dying. My impulse was to freak out, delete the backups, and start fresh, but I researched it instead and ended up moving them from the root of the drive to a directory, and it appears to have fallen back to what it was supposed to do in the event of a corrupt backup which is make a new full one. I don’t yet know which backup was corrupt, I hope it wasn’t the full that the earlier incremental ones were based on, and I’m dismayed to find errors after copying, but I probably should have used rsync instead of Nautilus.
EDIT: It looks like the backups weren’t actually damaged. It may have been that the lost+found directory in the root of the drive was causing problems.