Virtual Files and read only external storage folders break sync

Nextcloud version (eg, 29.0.5): 28.0.6
Operating system and version (eg, Ubuntu 29.04): docker nextcloud:28.0.6-apache
Apache or nginx version (eg, Apache 2.4.25): docker nextcloud:28.0.6-apache
PHP version (eg, 8.3): docker nextcloud:28.0.6-apache

The issue you are facing:

Is this the first time you’ve seen this error? (Y/N): Y

Steps to replicate it:

  1. Configure a external Storage Folder Folder and add the read Only Option in its configuration
  2. Configure Mac Client to use Virtual Files feature
  3. Sync the whole Folder and make all files avialable locally
  4. Tell Nextcloud Client to free up local Space

From now on thge sync will fail because the nextCloud Client set the Directories inside the Synced folder to read only. By that the client is unable to update directory content.