Ihr Lieben,
hier die Antwort vom Support:
If you enable an encrypted shared folder as team folder in Synology Drive, it will copy all files into the Drive database because the BTRFS clone command doesn't work for encrypted shared folders. This will cause that the used storage will be doubled.
We recommend to use Snapshot replication to keep file versions. Snapshot Replication won't take additional space for the first snapshot, after the first snapshot it will take space for the difference between the Snapshots.
Also kein Bug, sondern konzeptionell/technisch bedingt. Das ist schade. Leider verbrauchen die Snapshots bei mir auch den doppelten Speicherplatz, das habe ich jetzt beim Support auch mal angesprochen...
Andi!