Question about restore action without or with --force

[boiteacourriels]

Hello list,
I use rdiff-backup with debian 12 for my internal backups and locally on 
another computer also on debian 12 with ssh.
I use internally
rdiff-backup -v5  --fsync --new backup --print-statistics --include-
globbing-filelist $EXCLUDE $SOURCE $DESTINATION

I use locally
rdiff-backup -v5  --fsync --new backup --print-statistics --include-
globbing-filelist $EXCLUDE folder to backup $USER@IP::/ backup folder

It works perfectly.

Unfortunately I encounter a problem when restoring locally.
I use:
rdiff-backup -v5  --fsync restore --at now $USER@P:://what I want to 
restore where I want to restore.
I have this message:
rdiff-backup -v5  --fsync --new restore --at now /backup folder  /
destination folder 
* Run remote command ssh -C server rdiff-backup --terminal-verbosity 5 
--server
WARNING: this command line interface is obsolete and will disappear, 
start using the new one as described with '--new --help'.
* Starting the server
* The API version is 200 with the command b'ssh -C server rdiff-backup 
--terminal-verbosity 5 --server'
ERROR: Target path/destination folder exists and is not empty, call with 
'--force' to overwrite
ERROR: Action restore failed when checking step
* Cleaning
* Cleaning
If I use --force 
rdiff-backup -v5  --fsync --new --force restore --at now /backup folder  
/destination folder 
This removes all folders and files present in the destination folder but 
not present in the backup folder.
The destination folder:
- folder 1 present in the folder and restore
- folder 1 present in the folder and restore
- folder 3 empty not present in backup folder is deleted
- folder 3  with file and folder  not present in backup folder are 
deleted 
 i loss all file and folder create after the last backup 

Why such a behavior?
Would I make a mistake in my instructions.
Please help me to use rdiff-backup correctly.
Best regards.