Hi - Sorry to hear the trouble that you're having.
This setup is not supported by eCryptfs. The owncloud client is presumably making changes to /home/local/Documents.enc while the user is making changes to /home/sander/Documents. There's nothing keeping the filesystem object caches (page cache, inode cache, denty cache) for /home/local/Documents.enc in sync with the caches for /home/sander/Documents.
Hi - Sorry to hear the trouble that you're having.
This setup is not supported by eCryptfs. The owncloud client is presumably making changes to /home/local/ Documents. enc while the user is making changes to /home/sander/ Documents. There's nothing keeping the filesystem object caches (page cache, inode cache, denty cache) for /home/local/ Documents. enc in sync with the caches for /home/sander/ Documents.