Owncloud server filling up HD after restoring deleted files

Hey guys,

Yesterday I found out lots of files were deleted by a user on the server and restored them back to the previous location. However the disk space on the server shrunk from 900gb remaining to 72gb remaminig this morning.
No new files were added, just restored from the trash bin. How can I make the server have the same amount of disk it had before the recovery?
Seems it took some 700gb just restoring the files that were there a day ago.
Thanks!

Best guess: Delete and/or restore was during sync, creating tons of conflict files?