Restore with overwriting : "Input payload validation failed"

I installed burp-ui (burp version : 1.4.40), and i'm now running some tests.

While testing some restores on my servers, i saw a "Whether to overwrite existing files: " feature. This seemed very interesting, so i gave it a try, but when this option is checked (and without touching the other options), if i want to initiate the server restore, i have the "Input payload validation failed" message, and no "restore" file is created on the server.

For information, without the option checked, it works really fine.

Thanks in advance.