Critical Messages on the customer record will occasionally fail to expire. This can be caused by a data error, usually from conversions. If setting the Expiration Date does not resolve the issue, it will need SQL to investigate.
The critical message is not kept on the customer record though, it is found in SY_Critical_Message.
Select * from sy_critical_message where customer_id = ReplaceWithCustomer_ID
If you see the messages that are stuck, either with nulls or odd dates, you can set the messages to have an expiration date in the past.
Update sy_critical_message
Set Expires = ‘ReplaceWithYesterday’
Where customer_id = ReplaceWithCustomer_ID
