Data masking is a complex operation and can run into issues because of a variety of reasons- Data, Metadata, and Salesforce Platform limitations. DataMasker has a way to capture exceptions in a custom object. This functionality only needs to be enabled, if Cloud Compliance support requests so.
Here are the steps:
Step 1: Search Custom Metadata Type
In your Salesforce Org, search for “Custom Metadata Types”
Step 2: Update Metadata Value
Click on ‘Manage Records’ for ‘DM App Config’
Click on the ‘Edit’ link
Update the value to “True”
The value of ‘Label Capture_Exceptions’ is now successfully set to “True”. This means DataMasker will now capture metadata exceptions.