Undefined index: sequence-2 - Magento 2.2.2 EE

I ran into this issue today. This can happen when a product is disabled while a customer already has it in their cart. They will be unable to use their cart. You can fix this by finding their cart and removing the item from the cart.

Sadly Magento does not do this automatically.

I use this query to find out which quotes contain disabled products.

SELECT item_id, quote_id, quote_item.product_id, quote_item.store_id as 'quote_store_id' FROM quote_item LEFT JOIN catalog_product_entity_int as `status_default` ON status_default.entity_id = quote_item.product_id AND status_default.attribute_id = 97 AND status_default.store_id = 0 LEFT JOIN catalog_product_entity_int as `status_store` ON status_store.entity_id = quote_item.product_id AND status_store.attribute_id = 97 AND status_store.store_id = quote_item.store_id WHERE (status_store.value = 2 || (status_store.value IS NULL && status_default.value = 2)); 

To remove all items for disabled products, run:

DELETE FROM quote_item WHERE item_id IN(SELECT item_id FROM (SELECT * FROM quote_item) as `inner_quote_item` LEFT JOIN catalog_product_entity_int as `status_default` ON status_default.entity_id = inner_quote_item.product_id AND status_default.attribute_id = 97 AND status_default.store_id = 0 LEFT JOIN catalog_product_entity_int as `status_store` ON status_store.entity_id = inner_quote_item.product_id AND status_store.attribute_id = 97 AND status_store.store_id = inner_quote_item.store_id WHERE (status_store.value = 2 || (status_store.value IS NULL && status_default.value = 2)));