Unexpected error while listing existing assests

Problem/Motivation

When accessing
admin/config/development/asset-injector/css
or
admin/config/development/asset-injector/js

Drupal renders "The website encountered an unexpected error. Please try again later."

PHP log throws:
TypeError: implode(): Argument #2 ($array) must be of type ?array, string given in /var/www/web/modules/contrib/asset_injector/src/AssetInjectorListBuilder.php

Steps to reproduce

Enter mentioned URLS