Read only external storage is not downloaded to client

[jacotec]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

I have external storage mounted from my paperless-ngx DMS to Nextcloud,. The mount is "local storage" as the files are synced via Syncthing from the paperless VM to my Nextcloud VM, so they reside as a copy on the local disk.

The external storage is marked as "write protected" in the NC config.

All the files do appear in the Nextclod Web Interface, but they are not synced via the sync client to my PCs. No error message in the client, they are just "ignored".

As soon as I switch off the "write protected" in the external stroage config, the files are immediately synced to my harddisk.

Steps to reproduce

1. Mont an external storage with files and configure it as "Write protected" to prevent upload of files to it via Nextcloud
2. The folder with the files is configured to sync (virtual file system) in the NC client
3. Files in the folder and subfolders do not sync
4. Remove the "write protection"
5. Files are immediately synced

Expected behavior

Files of mounted "read only" external storage should be synced fully to the desktop.

Which files are affected by this bug

All files in the write protected external storage

Operating system

Windows

Which version of the operating system you are running.

Windows 10

Package

Appimage

Nextcloud Server version

25.0.5

Nextcloud Desktop Client version

3.7.4

Is this bug present after an update or on a fresh install?

Updated from a minor version (ex. 3.4.2 to 3.4.4)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

No response

Additional info

Debug archive of the client is too big to attach (176MB)