The appearance of this folder in your user accounts suggest you have a global External Storage mount called cephs3
configured in Nextcloud.
However, the urn:oid
suggests you are also utilizing an S3 bucket you either currently or formally configured as Primary Storage in Nextcloud.
These are two very different things. And the same S3 bucket should never be used for both.
See the File sharing section of the Admin Manual at https://docs.nextcloud.com. There are sections for both External Storage and Primary Storage.
We can only guess what you’re actively using since you didn’t fill out the support template.