[rdiff-backup-users] Computed SHA1 doesn't match

[Fabien SK]

Hi,

I use rdiff-backup through backupninja, and after doing a backup, if I
execute "rdiff-backup --verify /my/backup/directory", many files have
the following warning:

Warning: Computed SHA1 digest of (name of the file)
  (some digest AAA)
doesn't match recorded digest of
  (some other digest BBB)

If I verify the actual digest of one of these files in my data directory
and in the backup directory (using with the command "sha1sum"), the
digest is the same as AAA, but not the same as BBB (stored in the file
mirror_metadata.2007.[...].snapshot.gz)

I am currently using the following versions:
- Ubuntu: 7.04
- rdiff-backup: 1.1.5 (the one provided with my system)
- sha1sum: 5.97
- librsync1: 0.9.7-1
- python: 2.5.1-0ubuntu3

The backup is done locally (well, to a partition formatted in ext3 on an
USB drive).

I wonder what can be wrong. I did not see anything in the archives of
the mailing list or in the changelog.
I will try to reproduce it on a subset of my data, and if I can I will
try with a more recent version of rdiff-backup.
Any thought would be helpful.

Thank you for your attention.
Fabien