Some of the New Value data might disappear (have the broken icon instead of the value) when you import a solution that disables the Audit of the entity or if the Audit is already disabled and then you enable Audit.
It is a known issue and if you are working on online you will need to create a Service Request to the Support.
If you are OnPrem you will need to run the following SQL script to check and then clean the records:
Select * from AuditBase WHERE action = 104 OR action = 102
Action = 104 | Any Auditing Changes that are made at Organization level would get captured with code 104.
Action = 102 | Any Auditing Changes that are made at Entity level would get captured with code 102.
In order to retrieve the Audit value from the DB, we would need to run the following command:
DELETE from AuditBase WHERE action = 104 AND CreatedOn > ‘<date>’ || Action = 104 or 102, depending on the results we get the above SELECT query
After this, the values will show again.