Rsync checksum issue

[Laurent B]

Dear all,

I'm encountering a problem with one of my backup. For some files, the 
checksum calculation is failing leading to the following error :

For instance:

 >f......... Avion/avion-été-2020/pesee-log-nav-carbu.ods

WARNING: Avion/avion-été-2020/pesee-log-nav-carbu.ods failed 
verification -- update discarded (will try again).

The problem is the files are strictly identical on each endpoint:

- on the target:

root at nas:~/sauvegardes-manuelles# md5sum 
/srv/last-backup/Avion/avion-été-2020/pesee-log-nav-carbu.ods
44807654dcd7eb0ea3bfa9f47d7eadf7 
/srv/last-backup/Avion/avion-été-2020/pesee-log-nav-carbu.ods

- on the source:

root at laurent-laptop:/home/laurent/perso/Avion# md5sum 
avion-été-2020/pesee-log-nav-carbu.ods
44807654dcd7eb0ea3bfa9f47d7eadf7 avion-été-2020/pesee-log-nav-carbu.ods

The sha256sum is the same on both endpoints too.

Do you have an idea ?

Thanks,

Laurent