It isn't a virus or some sort of FTP compression.
It could be a couple of things going on:
For example, if the server is running Linux and your desktop is running Windows it is likely that your server and desktop are set to display file sizes differently.
In some operating systems, file sizes tend to be expressed mebibytes (e.g. 1 GiB = 1,024 MiB) while ...
Open CPanel, go to Files and then FTP accounts. Look at your FTP account to see what the initial directory is (you can compare using CPanel's File Manager in the same section). It sounds like you're FTP account is starting in the wrong location.
Or, you might also want to look at using File Manager to move and copy files.
In the ftp you may start in a directory dedicated to your user.
So you must be sure that your user has access to the same directory than the wordpress is uploaded in.
If true, you should know that the ftp landing directory is often relative.
For example : /home/user/public_html may lead in the connexion to the directory displayed as / and contains ...
Create .ftpaccess file in directory that needs to be read-only for account email@example.com.
Content of the .ftpaccess file:
Commands in .ftpaccess file are recursive (i.e. affects all the files
in the current directory and any subdirectory). ...
Filezilla properly downloads files and directories but responds with error when trying to download symlinks to local.
550 Can't open [filename]: No such file or directory
Actually, this is not Filezilla producing the error but Filezilla is just showing the error message from the FTP server. It is likely that the symlink does not resolve to an existing file ...
It's the browser cache that does this.
For chrome go to the three dots on the right corner and click 'more tools'.
Then select 'clear browsing data ' and make sure cache is enabled.
When you did this close chrome and reopen the site.