I encounter the same issue. I run command “wp cache flush” just after installing the plugin:
PHP Fatal error: Call to a member function register_question_type() on a non-object in /var/www/test/wp/wp-content/plugins/quiz-master-next/php/question-types.php on line 14
PHP Stack trace:
PHP 1. {main}() /usr/local/bin/wp:0
PHP 2. include() /usr/local/bin/wp:4
PHP 3. include() phar:///usr/local/bin/wp/php/boot-phar.php:5
PHP 4. WP_CLI\Runner->start() phar:///usr/local/bin/wp/php/wp-cli.php:21
PHP 5. WP_CLI\Runner->load_wordpress() phar:///usr/local/bin/wp/php/WP_CLI/Runner.php:721
PHP 6. require() phar:///usr/local/bin/wp/php/WP_CLI/Runner.php:770
PHP 7. do_action() phar:///usr/local/bin/wp/php/wp-settings-cli.php:302
PHP 8. call_user_func_array() /var/www/test/wp/wp-includes/plugin.php:525
PHP 9. qmn_question_type_multiple_choice() /var/www/test/wp/wp-includes/plugin.php:525
