Different sizes in nextcloud and nextcloud client

Hi to all,
I have a small box , AMD Ryzen 2600X 6 core , 8MB ram, ASRock Fatality X379 Gaming-ITX/ac Motherboard booting on an SSD. Intel 545s sata3 128MB NAND, system running Nextcloud 13.
Now… Nextcloud reports I have 331.1GB used and a green tick on the screen. I assume that means it has finished syncing the data across ? However the box that is syncing data, I get to look at the Nextcloud folder is reported 530.8 GB in size.
Is there a problem somewhere? Or is that normal?

If you have deleted files or different versions of one file, this can contribute to real usage but only the actual files are shown in the user quota (trash bin and versions are managed in a way, that they never use up all space).