Removing a meal (or clearing the day) only deletes the link between the meal and the date's menu; it does not touch existing checkouts, subscription selections or production counts - those still reference the meal. New customers simply cannot pick it any more for that date. Check the ORDERS column first: if it is above zero, consider keeping the meal (or handling those orders manually). Note that cloning explicitly protects meals with orders, but the manual trash/Clear actions do not.