PHP warning with new installation

I’m getting the following warning on a new install of Sucuri, using Windows.

WARNING: E:\web\htdocs\wordpress\wp-content\plugins\sucuri-scanner\src\hardening.lib.php:98 - fopen(E:\web\htdocs\wordpress//E:/web/htdocs/wordpress/wp-content/uploads/sucuri/.htaccess): failed to open stream: No such file or directory

The bug appears to be in the static function htaccess(). On my localhost, that method is returning the following path name to .htaccess:

E:\web\htdocs\wordpress//E:/web/htdocs/wordpress/wp-content/uploads/sucuri/.htaccess

In turn that seems to be caused because $folder being passed to the htaccess method has forward slashes, while ABSPATH has backslashes (although with a forward slash at the end, thanks to lines 11-13 of wp-admin/load-scripts.php).