Backups not working after running out of space

Using rdiff-backup 2.2.2 on Windows 10 Pro 22H2, I have a scheduled task that runs my system backup PowerShell script at 2 AM every morning.  The script runs rdiff-backup several times to backup several different directories.  A few days ago one of the backups failed because the NAS volume containing targetdir filled up.  I took some remedial steps that didn't help, but at this point I don't remember exactly what I did.  I do know that this first thing I tried, not thinking very careful, and realizing that I had recently created some large files in sourcedir that I didn't need any more, I deleted those files and tried doing a backup running rdiff-backup manually (incorrectly thinking rdiff-backup would remove some files from targetdir).  Of course since rdiff-backup is creating incremental backups, and targetdir was still full, that backup failed too.  At some point I increased the size of the NAS volume, and here is where my memory is failing me. I probably tried running rdiff-backup manually again.   Either then, or shortly thereafter, I started getting "regressing destination" and then rdiff-backup failing whenever I tried to backup or verify, so I attempted to follow the instructions in FAQ item 15.  I did some other troubleshooting that I don't remember, but the backups are still failing.

Now, running "rdiff-backup.exe backup --print-statistics  ..." doesn't print the expected statistics (so I assume it didn't backup anything) and produces the following output:

C:\Users\pcanning\rdiff-backup-2.2.2-64\rdiff-backup.exe : WARNING: Previous backup seems to have failed, regressing destination now
At line:1 char:1
+ C:\Users\pcanning\rdiff-backup-2.2.2-64\rdiff-backup.exe backup --pri ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (WARNING: Previo...destination now:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError
 
WARNING: Could not find mirror metadata file. Metadata will be read from filesystem instead
Fatal Error: No metadata for time Thu Nov  9 02:35:42 2023 (1699526142) found, cannot regress
NOTE: Symbolic links excluded by default on Windows
NOTE: Regressing to date/time Thu Nov  9 02:35:42 2023

Running "rdiff-backup.exe verify ..." produces the following output:

C:\Users\pcanning\rdiff-backup-2.2.2-64\rdiff-backup.exe : WARNING: Two different times for current mirror found
At line:1 char:1
+ C:\Users\pcanning\rdiff-backup-2.2.2-64\rdiff-backup.exe verify \\nas ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (WARNING: Two di...nt mirror found:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError
 
WARNING: Could not find mirror metadata file. Metadata will be read from filesystem instead
WARNING: Mirror metadata not found, reading from directory

followed by many lines saying

WARNING: Cannot find SHA1 digest for file ..., perhaps because this feature was added in v1.1.1

and ending with the line:
NOTE: Verification found 1428 files without hash, all others could be verified successfully

Any suggestions for how to get my backups (and verifies) working again?

thanks,
Peter