Update Version 6.0.0 caused an php error

Hi There!

We just updated to WC 6.0.0 on our test page and received the following error:

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Creating default object from empty value

wp-content/themes/mh-magazine/includes/updater/theme-updater-class.php:120
EDD_Theme_Updater->theme_update_transient()
wp-includes/class-wp-hook.php:305
apply_filters(‘site_transient_update_themes’)
wp-includes/option.php:1945
get_site_transient()
wp-includes/update.php:790
wp_get_update_data()
wp-admin/menu.php:33

PHP Warning: Creating default object from empty value in /kunden/xx_xx/webseiten/testseite.hello-world.net/wp-content/themes/mh-magazine/includes/updater/theme-updater-class.php on line 120

thnx for helping
Nick