No redirect created after changing alias

[hugopeek]

From the description under 301 redirects:

To help you, SEO Tab automatically adds 301 redirects when you change the URL of a page. To delete a 301 redirect, right-click on it.

So if I understand correctly, the plugin should add a new entry there when I change the alias, right? Unfortunately that's not happening in my case.. One error in log:

[2021-01-14 06:52:14] (ERROR @ /home/xxxxxxx/www/core/cache/includes/elements/modplugin/100021.include.cache.php : 109) PHP warning: Invalid argument supplied for foreach()

I upgraded from v1 to v2, but if I check the old manager, this problem is also there. No errors there in log though.

Environment:
MODX 2.7.2 / 2.8.1
SEOTab 1.2.1-pl / 2.2.3-pl
PHP 7.3 / Nginx / MariaDB