Internal Server Error for any attempt to download or upload to a shared folder

I’m concerned that this issue has come about because files that had been stored and accessible on NextCloud (NC) are now gone.

I would point out that this docker container maps volume /var/www/html/ to local drive at /srv/nextcloud/html which is remote mounted using a curlsftpfs command in the system’s /etc/fstab file.
This mount point goes to a Network Attached Storage (NAS).

Here are some the symptoms we have:

  1. Accessing older shared folders:
    If anyone navigates to shared (shared by someone else) folder and attempts to download we get an “Internal Server Error”, and the log shows, among other log entries, the cut/paste log entry below.
    And, and blue screen is displayed as attached. These are older folders and all are marked shared.
[PHP] Error: Error: fopen(/var/www/html/data/<username removed>/files/public files/OfficeSupportPosition-v2.docx): failed to open stream: No such file or directory at /var/www/html/lib/private/Files/Storage/Local.php#355 at <<closure>>

 0. <<closure>>
    OC\Log\ErrorHandler::onError(2, "fopen(/var/www/ ... y", "/var/www/html/l ... p", 355, {path: "files/pu ... "})
 1. /var/www/html/lib/private/Files/Storage/Local.php line 355
    fopen("/var/www/html/d ... x", "r")
 2. /var/www/html/lib/private/Files/Storage/Wrapper/Wrapper.php line 300
    OC\Files\Storage\Local->fopen("files/public fi ... x", "r")
 3. /var/www/html/custom_apps/files_accesscontrol/lib/StorageWrapper.php line 325
    OC\Files\Storage\Wrapper\Wrapper->fopen("files/public fi ... x", "r")
 4. /var/www/html/lib/private/Files/View.php line 1165
    OCA\FilesAccessControl\StorageWrapper->fopen("files/public fi ... x", "r")
 5. /var/www/html/lib/private/Files/View.php line 1001
    OC\Files\View->basicOperation("fopen", "/public files/O ... x", ["read"], "r")
 6. /var/www/html/apps/dav/lib/Connector/Sabre/File.php line 434
    OC\Files\View->fopen("public files/Of ... x", "r")
 7. /var/www/html/3rdparty/sabre/dav/lib/DAV/CorePlugin.php line 90
 8. /var/www/html/3rdparty/sabre/event/lib/WildcardEmitterTrait.php line 89
    Sabre\DAV\CorePlugin->httpGet(Sabre\HTTP\Request {}, Sabre\HTTP\Response {})
 9. /var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php line 474
    Sabre\DAV\Server->emit("method:GET", [Sabre\HTTP\Requ ... }])
10. /var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php line 251
    Sabre\DAV\Server->invokeMethod(Sabre\HTTP\Request {}, Sabre\HTTP\Response {})
11. /var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php line 319
12. /var/www/html/apps/dav/appinfo/v1/webdav.php line 84
13. /var/www/html/remote.php line 167
    require_once("/var/www/html/a ... p")

GET /remote.php/webdav/public%20files/OfficeSupportPosition-v2.docx?downloadStartSecret=<secret removed>
from by <user name removed>  at 2023-03-17T17:12:12+00:00

2) Accessing newly created shared folders and files:

If two of us create new folders and share the with each other, we can access and download a file we upload to these folders… no problem.

So, it would seem to do with older files.

When attached to the nextcloud_app container’s bash shell and try to navigate to where files where unable to be found, sure enough the files that failed to download are not there.

So could I have lost those files? or is there some way these files still exist but are hidden?

NextCloud 20.0.4
Ubuntu 18.04
docker 2.10.7