Text Column Issue: New Rows Not Populating with Existing Data

Issue with Text column: When I have a text column which has been populated at the column header (every row has the same content) and I add new roles to table, it does not populate the new rows with the text data. Screenshot shows the existing rows which were in the table when that column (spam words) was created are populated, but the new rows from 1998 onwards are not. This then prevents other columns running.