Wrapped `$ftpSite` in `isset()` where $ftpSite was a part of a condition for existence testing and was using the simplified mode for the check. The simplified mode resulted in the following notice being produced when no data was present in the `$ftpSite` variable.
> PHP Notice: Undefined variable: ftpSite in /var/www/html/ice/lib/file-control-xhr.php on line 518
While the error pertains specifically to line 518, this adjustment was applied to all condition checks on this variable.