You may want to add a suppression list to a mailing. After importing, you may observe that the system indicates that all contacts from this list were uploaded successfully. On many occasions, the number of contacts uploaded is less than the actual number of contacts in the list to be imported, suggesting that the list might not be fully uploaded.
This difference in the number of contacts uploaded and the actual number of contacts in the suppression list is usually because of duplicate or invalid contacts. Since Lyris LM does not allow duplicate email addresses in its lists, the duplicates from the suppression list may be skipped.