Uploading files to group folder on Nextcloud with S3 multibucket as primary storage causes much load on host

I have nextcloud instance which is configured to use S3 multibucket objectstorage as primary storage. I am also using group folders app with my team. Last time I noticed strange flow of uploading files to group folders on my instance compering to uploading files to simple user folder.

So as my investigation is not wrong, the flow of uploading files to group folders is as follow:

  1. User put file to group folder
  2. The upload process starts, if file is large enough it starts to be send in chunks to Nextcloud instance, server forwards them to S3 bucket (bucket assigned to user as stands in oc_mounts database table)
  3. When upload to bucket gets finished, Nextcloud server starts to download (just uploaded) file (also in chunks) and upload it again to another S3 bucket (bucket assigned to group folder as stands in oc_mounts database table) .
  4. User get notified that upload is finished

The third point could be redundant if first upload would be direct to storage assigned to group folder, such behaviour is equivalent to uploding files to simple user folders.

Below two screenshot from my monitoring system, first ilustrating instance load (CPU|RAM|DISK|NETWORK) during upload of 4 files each 1GB size to group folder on my development instance, second with the same situation on the same instance but uplod to simple folder.

Is such behaviur is normal, is it possible to change it by some configuration?

My nextcloud version is 27.1.8, S3 is private Ceph.