Hi ilexeo, rabidsloth
As you said, only the new version 4.0.1 supports epsv command and it might cause this issue. We remember we have replied Mr. Rabidsloth about the epsv command. Apparently, we need do more test about it.
Could you please tell us the version of filezilla you are using. Or other FTP client's name and version. And we would appreciate if you can provide a test account for us. (Email to firstname.lastname@example.org
Thank you very much.