Error: ftp_nlist() expects parameter 1 to be resource

Hi,
after upgrade I noticed this error in my error log after upgrade to 5.7.2

HP Warning: ftp_nlist() expects parameter 1 to be resource, null given inwp-admin/includes/class-wp-filesystem-ftpext.php

2021/05/23 08:39:15 [error] 1168#1168: *318 FastCGI sent in stderr: "PHP message: PHP Warning:  ftp_nlist() expects parameter 1 to be resource, null given in ***/wp-admin/includes/class-wp-filesystem-ftpext.php on line 420PHP message: PHP Warning:  ftp_pwd() expects parameter 1 to be resource, null given in ***/wp-admin/includes/class-wp-filesystem-ftpext.php on line 230PHP message: PHP Warning:  ftp_pwd() expects parameter 1 to be resource, null given in ***/wp-admin/includes/class-wp-filesystem-ftpext.php on line 230PHP message: PHP Warning:  ftp_pwd() expects parameter 1 to be resource, null given in ***/wp-admin/includes/class-wp-filesystem-ftpext.php on line 230PHP message: PHP Warning:  ftp_nlist() expects parameter 1 to be resource, null given in ***/wp-admin/includes/class-wp-filesystem-ftpext.php on line 420PHP message: PHP Warning:  ftp_pwd() expects parameter 1 to be resource, null given in ***/wp-admin/includes/class-wp-filesystem-ftpext.php on line 230PHP message: PHP Warning:  ftp_pwd() expects parameter 1 to be resource, null given in ***/wp-admin/includes/class-wp-filesystem-ftpext.php on line 230PHP message: PHP Warning:  ftp_pwd() expects parameter 1 to be resource, null given in ***/wp-admin/includes/class-wp-filesystem-ftpext.php on line 717" while reading response header from upstream, client: 127.0.0.1, server: termoflor.lo, request: "GET /wp-admin/post-new.php?post_type=page HTTP/1.1", upstream: "fastcgi://unix:/var/run/php/php7.4-fpm.sock:", host: "termoflor.lo", referrer: "https://xxx/wp-admin/plugins.php?plugin_status=all&paged=1&s"

It stops if I disable Kadence blocks, that’s how I know it originates form your plugin. How can I fix it?
Regards, G.