I see these errors on several actions actually:
1.
172.18.0.2 - - [28/Aug/2019:11:37:24 +0000] "GET /wp-json/wc/v2/products/attributes/?oauth_consumer_key=****&oauth_nonce=**&oauth_signature_method=HMAC-SHA256&oauth_timestamp=1566992244&oauth_version=1.0&lang=en&oauth_signature=***%3D HTTP/1.1" 200 1925 "-" "dash/2 CFNetwork/975.0.3 Darwin/17.7.0"
[Wed Aug 28 11:37:24.824650 2019] [php7:error] [pid 81] [client 172.18.0.2:60884] PHP Fatal error: Uncaught Error: Call to a member function get() on null in /var/www/html/wp-content/plugins/woocommerce/includes/data-stores/class-wc-customer-data-store-session.php:96\nStack trace:\n#0 /var/www/html/wp-content/plugins/woocommerce/includes/class-wc-data-store.php(159): WC_Customer_Data_Store_Session->read(Object(WC_Customer))\n#1 /var/www/html/wp-content/plugins/woocommerce/includes/class-wc-customer.php(116): WC_Data_Store->read(Object(WC_Customer))\n#2 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Helpers.php(436): WC_Customer->__construct(1, true)\n#3 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Helpers.php(358): AtumMultiInventory\Inc\Helpers::get_visitor_location()\n#4 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Hooks.php(1301): AtumMultiInventory\Inc\Helpers::get_product_inventories_sorted(43)\n#5 /var/www/html/wp-includes/class-wp-hook.php(286): AtumMultiInventory\Inc\Hooks->get_manage_stock(false, Object(WC_Product_Simple))\n#6 /var/www/html/wp-i in /var/www/html/wp-content/plugins/woocommerce/includes/data-stores/class-wc-customer-data-store-session.php on line 96
2.
172.18.0.2 - - [29/Aug/2019:05:24:17 +0000] "GET /wp-json/wc/v2/products/tags/?oauth_consumer_key=***&oauth_nonce=&oauth_signature_method=HMAC-SHA256&oauth_timestamp=1567056289&oauth_version=1.0&hide_empty=true&per_page=100&order=desc&orderby=count&lang=en&oauth_signature=***%3D HTTP/1.1" 200 606 "-" "dash/3 CFNetwork/975.0.3 Darwin/18.7.0"
[Thu Aug 29 05:24:18.725517 2019] [php7:error] [pid 96] [client 172.18.0.2:34204] PHP Fatal error: Uncaught Error: Call to a member function get() on null in /var/www/html/wp-content/plugins/woocommerce/includes/data-stores/class-wc-customer-data-store-session.php:96\nStack trace:\n#0 /var/www/html/wp-content/plugins/woocommerce/includes/class-wc-data-store.php(159): WC_Customer_Data_Store_Session->read(Object(WC_Customer))\n#1 /var/www/html/wp-content/plugins/woocommerce/includes/class-wc-customer.php(116): WC_Data_Store->read(Object(WC_Customer))\n#2 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Helpers.php(436): WC_Customer->__construct(1, true)\n#3 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Helpers.php(358): AtumMultiInventory\Inc\Helpers::get_visitor_location()\n#4 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Hooks.php(1301): AtumMultiInventory\Inc\Helpers::get_product_inventories_sorted(43)\n#5 /var/www/html/wp-includes/class-wp-hook.php(286): AtumMultiInventory\Inc\Hooks->get_manage_stock(false, Object(WC_Product_Simple))\n#6 /var/www/html/wp-i in /var/www/html/wp-content/plugins/woocommerce/includes/data-stores/class-wc-customer-data-store-session.php on line 96
3.
172.18.0.2 - - [29/Aug/2019:05:15:45 +0000] "GET /wp-json/wc/v2/products/categories/?oauth_consumer_key=****&oauth_nonce=**&oauth_signature_method=HMAC-SHA256&oauth_timestamp=1567055777&oauth_version=1.0&hide_empty=true&per_page=100&order=desc&orderby=count&lang=en&oauth_signature=***%3D HTTP/1.1" 200 3967 "-" "dash/3 CFNetwork/975.0.3 Darwin/18.7.0"
[Thu Aug 29 05:15:48.130088 2019] [php7:error] [pid 439] [client 172.18.0.2:33838] PHP Fatal error: Uncaught Error: Call to a member function get() on null in /var/www/html/wp-content/plugins/woocommerce/includes/data-stores/class-wc-customer-data-store-session.php:96\nStack trace:\n#0 /var/www/html/wp-content/plugins/woocommerce/includes/class-wc-data-store.php(159): WC_Customer_Data_Store_Session->read(Object(WC_Customer))\n#1 /var/www/html/wp-content/plugins/woocommerce/includes/class-wc-customer.php(116): WC_Data_Store->read(Object(WC_Customer))\n#2 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Helpers.php(436): WC_Customer->__construct(1, true)\n#3 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Helpers.php(358): AtumMultiInventory\Inc\Helpers::get_visitor_location()\n#4 /var/www/html/wp-content/plugins/atum-multi-inventory/classes/Inc/Hooks.php(1301): AtumMultiInventory\Inc\Helpers::get_product_inventories_sorted(43)\n#5 /var/www/html/wp-includes/class-wp-hook.php(286): AtumMultiInventory\Inc\Hooks->get_manage_stock(false, Object(WC_Product_Simple))\n#6 /var/www/html/wp-i in /var/www/html/wp-content/plugins/woocommerce/includes/data-stores/class-wc-customer-data-store-session.php on line 96