Hi there. We have an ongoing problem and I just tested it again with macOS client 2.6.2 and Nextcloud server 16.0.7.
A folder is owned by a central user. The folder is large in size. For testing, I used a folder with 10 Gb worth of photos.
The folder is shared with a user with a Nextcloud account. The user RENAMES the root folder that was shared with them either to organize the folder or to shorten the name.
When the folder is renamed on the macOS desktop (macos Mojave and NC desktop client version 2.6.2), on the server the action is reflected as a DELETE. That action deletes the folder from all other users that it was shared with. The folder is then copied up to the server again from the computer of the person who deleted it and it is pushed out again to all users who had access to it before. The other users do not see the rename but the folder simply disappears for a period of time.
We have this happen when the folder is renamed and an identically appearing process happens when shared folders are moved into another folder to ‘organized’ the folders shared with them.
This is similar to a 2017 NC topic - Moving a shared folder breaks the link to the shared folder and deletes files and Folder move deleted and a GitHub issue - https://github.com/nextcloud/server/issues/5674. And one that is not mine - Renaming and moving often causes uploading and downloading
Thank you for the help!