Also have been experiencing this problem. Our site uses WooCommerce as well. The log files show thousands of lines like the following:
[10-Aug-2017 16:12:12 UTC] PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 262144 bytes) in /.../wp-includes/cache.php on line 123
[10-Aug-2017 16:12:12 UTC] PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 262144 bytes) in /.../wp-includes/load.php on line 677
[10-Aug-2017 16:16:27 UTC] WordPress database error Not unique table/alias: 'tm' for query SELECT t.*, tt.*, tm.meta_key, tm.meta_value , tm.meta_value FROM wp_terms AS t INNER JOIN wp_term_taxonomy AS tt ON t.term_id = tt.term_id LEFT JOIN wp_termmeta AS tm ON (t.term_id = tm.term_id AND tm.meta_key = 'order') LEFT JOIN wp_icl_translations icl_t
ON icl_t.element_id = tt.term_taxonomy_id
AND icl_t.element_type IN ('tax_faq_category','tax_tribe_events_cat') LEFT JOIN wp_termmeta AS tm ON (t.term_id = tm.term_id AND tm.meta_key = 'order') WHERE tt.taxonomy IN ('faq_category', 'product_type', 'product_visibility', 'product_cat', 'product_tag', 'product_shipping_class', 'tribe_events_cat') AND ( ( icl_t.element_type IN ('tax_faq_category','tax_tribe_events_cat') AND icl_t.language_code = 'en' )
OR icl_t.element_type NOT IN ('tax_faq_category','tax_tribe_events_cat') OR icl_t.element_type IS NULL ) GROUP BY t.term_id ORDER BY tm.meta_value+0 ASC, CAST(tm.meta_value AS SIGNED) ASC, t.name ASC made by do_action_ref_array, WP_Hook->do_action, WP_Hook->apply_filters, BackWPup_Cron::run, BackWPup_Cron::cron_active, BackWPup_Job::start_http, BackWPup_Job->run, BackWPup_JobType_WPEXP->job_run, get_terms, WP_Term_Query->query, WP_Term_Query->get_terms
[10-Aug-2017 16:17:27 UTC] PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 20480 bytes) in /.../wp-content/plugins/woocommerce/includes/abstracts/abstract-wc-data.php on line 586
[10-Aug-2017 16:17:27 UTC] PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 262144 bytes) in /.../wp-includes/pluggable.php on line 69