Vault size on a cloud drive

Hi, I am using Win10 and I have installed a vault on a Pcloud drive. Everything is working fine, however what puzzles me is the size of the vault. The total size of all files stored in the vault is 17MB, but the size of the vault is 3.89GB. Is there any possibility to reduce the size?
I tried to find a question with a similar background but without success.

Are you looking at the size of the virtual drive, or the size of the actual encrypted files on your disk?

The size of the virtual drive was shown as 4GB, which was what I got as free drive volume from Pcloud. The size of the vault was shown as 3.89GB. However after a restart of my PC the sizes were shown correctly. No idea what has happened. I will close this ticket