Why is data for a custom Attendee Information field not writing to Salesforce?

If all but one or a subset of custom Attendee Information fields is properly writing to the Tickets records for an event registration, the ones which are failing may be due to a difference in the API Name between the custom field on the Ticket Temp and Ticket object.

For instance, if each field has a label in Salesforce of "What is your meal preference?" but one object has the API Name of Meal_Preference__c and the other of What_Meal_Preference__c, the data will not transfer properly from the Ticket Temp to the Ticket object on Lead conversion.

To review the process of adding custom fields, check out Adding custom fields from Salesforce to Attendee Information form.