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Sorry to hear you’re facing problems 
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Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version (eg, 29.0.5): 29.0.4
Operating system and version (eg, Ubuntu 24.04): Debian 12.7
Apache or nginx version (eg, Apache 2.4.25): 2.4.62
PHP version (eg, 8.3): 8.2.23
The issue you are facing:
Nextcloud server mounts an NFS share and some external storage “Local” folder are configured to access NFS share subfolders
Let say /mnt/share is the mount point
Those are some folders:
folderA Local /mnt/share/folderA
folderB Local /mnt/share/folderB
folderC Local /mnt/share/folderC
NFS server allows apache to access the whole share r/w via ACLs
Manual occ files:scan -all runs smooth with no errors
For all folders “Check for changes” is set to “Once every direct access” BUT when users access the shares sometimes they have updated file/folder list, sometimes not.
This happens more often on larger folders