MainWP Childをインストールした環境で、WordPress 上から unitone.zip をインストールしようとすると Fatal error

[inc2734]

• MainWP Child（v4.3.0.1)
• unitone（v4.3.2）

Fatal error: Uncaught TypeError: Illegal offset type in isset or empty in /home/hogehoge/hogehoge.com/public_html/unitone/wp-includes/class-wp-paused-extensions-storage.php:133
Stack trace: #0 /home/hogehoge/hogehoge.com/public_html/unitone/wp-includes/class-wp-theme.php(461): WP_Paused_Extensions_Storage->get(Object(WP_Theme))
#1 /home/hogehoge/hogehoge.com/public_html/unitone/wp-includes/theme.php(131): WP_Theme->__construct(Object(WP_Theme), '/home/hogehoge/h...')
#2 /home/hogehoge/hogehoge.com/public_html/unitone/wp-content/plugins/mainwp-child/class/class-mainwp-child-actions.php(298): wp_get_theme(Object(WP_Theme))
#3 [internal function]: MainWP\Child\MainWP_Child_Actions->callback_upgrader_process_complete(Object(Theme_Upgrader), Array)
#4 /home/hogehoge/hogehoge.com/public_html/unitone/wp-content/plugins/mainwp-child/class/class-mainwp-child-actions.php(150): call_user_func_array(Array, Array)
#5 /home/hogehoge/hogehoge.com/public_html/unitone/wp-includes/class-wp-hook.php(308): MainWP\Child\MainWP_Child_Actions->callback(Object(Theme_Upgrader), Array)
#6 /home/hogehoge/hogehoge.com/public_html/unitone/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)
#7 /home/hogehoge/hogehoge.com/public_html/unitone/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#8 /home/hogehoge/hogehoge.com/public_html/unitone/wp-admin/includes/class-wp-upgrader.php(859): do_action('upgrader_proces...', Object(Theme_Upgrader), Array)
#9 /home/hogehoge/hogehoge.com/public_html/unitone/wp-admin/includes/class-theme-upgrader.php(250): WP_Upgrader->run(Array)
#10 /home/hogehoge/hogehoge.com/public_html/unitone/wp-admin/update.php(324): Theme_Upgrader->install('/home/hogehoge/h...', Array
#11 {main} thrown in /home/hogehoge/hogehoge.com/public_html/unitone/wp-includes/class-wp-paused-extensions-storage.php on line 133