Hi, I’m facing almost the same problem: I receive the error when choosing paypal to buy an event ticket, other payments, like bill, german Nachname, etc. work fine. However, the error log is about an ticket pdf, here is the error-log:
Fatal error: Uncaught Error: Call to a member function get_item() on boolean in /www/htdocs/w014ffa3/2f2019.nina-eckhardt.de/wp-content/plugins/yith-event-tickets-for-woocommerce/includes/functions.yith-wcevti.php:158 Stack trace: #0 /www/htdocs/w014ffa3/2f2019.nina-eckhardt.de/wp-content/plugins/yith-event-tickets-for-woocommerce/includes/functions.yith-wcevti.php(270): yith_wcevti_set_args_mail_template(Object(WP_Post)) #1 /www/htdocs/w014ffa3/2f2019.nina-eckhardt.de/wp-content/plugins/yith-event-tickets-for-woocommerce/includes/functions.yith-wcevti.php(222): yith_wcevti_ticket_to_pdf(”) #2 /www/htdocs/w014ffa3/2f2019.nina-eckhardt.de/wp-content/plugins/yith-event-tickets-for-woocommerce/includes/class.yith-event-tickets.php(298): yith_wcevti_create_pdf(”) #3 /www/htdocs/w014ffa3/2f2019.nina-eckhardt.de/wp-includes/class-wp-hook.php(286): YITH_Tickets->attach_items_pdf_mail(Array, ‘customer_proces…’, Object(WC_Order)) #4 /www/htdocs/w014ffa3/2f2019.nina-eckhardt.de/wp-includes/plugin.php(203): WP_Hook->apply_filter in /www/htdocs/w014ffa3/2f2019.nina-eckhardt.de/wp-content/plugins/yith-event-tickets-for-woocommerce/includes/functions.yith-wcevti.php on line 158
If you need more information (WP 4.9.8., Divi-Theme, Woocommerce, germanized, paypal), please let me know!
Kind regards
Dennis