Great question — answering as the UphillTech team:
To understand the problem deeply, try to mount with --verbose option, i.e. mount -t cifs //$server/$share/$subfolderB /mnt/dirB --verbose The possible reasons of the problem can be wrong inode numbers or caching. As workaround for the inode numbers problem try this options (one of them): --serverino --noserverino Also try different caching methods (one of them): --cache=none --cache=strict --cache=loose Read mount.cifs(8) additionally.
Full answer by Bob: https://unix.stackexchange.com/a/462688 (CC BY-SA 4.0).
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