Renamed and deleted folders are recreated by users when syncing

Hi,
I’m administering a self-hosted ownCloud instance (server details below) with about 10 users.
All of these users operate on a shared folder, owned by one of them.

They notified several times to me the following unwanted behavior:

  • sometimes, after one of them has renamed or deleted a sub-folder inside the shared one, this folder reappears either duplicated with the original name or as a new upload (if previously deleted).
    The activity log shows the duplicated / re-uploaded folder as created by another user via either the desktop Windows client or the iOS app.

I’ve checked on the server’s filesystem and the folder is indeed physically present on disk (so it shouldn’t just be a database-related bug).

This seems to happen when the client or the app are synced, although it appears to be somewhat random.

I’m including here the details for the iOS app, since this is the most recent occurrence. I don’t have the app’s logs, though.

I’m not including the server and owncloud logs (they’re quite large), but I could send them separately.

Steps to reproduce

NOTE: the iOS app was set on using virtual files

  1. Rename or delete a folder within a shared superior folder
  2. Another user syncs the iOS app or the desktop client (not clear if related to virtual files in this case).

Expected behaviour

When renaming or deleting a folder, the clients should see that it has been changed / removed when syncing.

Actual behaviour

When the other user syncs, the folder is recreated / re-uploaded with the original name.

Server configuration

Web server:

Apache 2.4.29 on Ubuntu 18.04

Database:

MySQL 8.0.26

PHP version:

7.3.29

ownCloud version:

10.7.0.4

Storage backend (external storage):

N/A

Client

iOS version:

14.6

ownCloud app version:

11.6.1 build 195

Device model:

iPad (not sure which exact model)

No possible solutions for this problem?