The "Limit Incident Data Retention" response rule is not retaining attachment for some incidents when the attachment size is large. The incident reflects the original file as abc.doc.txt
Component : DLP Endpoint Prevent
This behavior is as designed. If data retention is enabled and the original file is larger than the "incidentHandler.MAX_FILE_SIZE" limit, the actual original file is renamed from abc.doc to abc.doc.txt. The default limit is 30MB.
You do have an option to increase this limit but consider checking the endpoints performance/resources and network bandwidth usage before this change.
To modify this limit: