Disk size on local server doesn't match after running garbage colletion

We using seafile 6.3.4 community edition with 9,8 TB data.
So there is problem, we have disk size around 13 TB that used for seafile data only. After run garbage collection, with 9,8 TB data on Seafile GUI, the free size of disk shoud be arround 3 TB right ? but in reality, the free disk is just arround 800 GB.

Is there any ideas, what could eat up our free disk ?

FYI, we also dont keep history retention period …

I think its related to “The files deleted by the last action will not be removed by GC for safety reason”. Then my question is how we know which library is it ? so i can add or delete file on that library …

Because i have arround 30k libraries and there is no trash file