'unkown_folders" during backup/restore operation

Hi,

We are restoring on three zimbra servers (8.8.9), the backup we had for a single server with 8.0.9. Servers 2 and 3 are still restoring items but server 1 already finished. We noticed that for some users, the folders had been restored with the wrong name. It looks like this:

Any idea what could be happening?

Thanks!