hello,
According to the fix notes of latest SEP version i.e. SEP 12.1 RU2, issue is resolved with this release.
Repeated detection of DWHxxxx.tmp as a threat
Fix ID: 2718341
Symptom: Repeated detection of DWHxxxx.tmp as a threat when a Defwatch scan runs on Quarantined items.
Solution: Increased Defwatch scan performance and moved the temporary extraction folder from %TEMP% to Application Data to avoid conflicts with Windows Search Indexer.
Reference: New fixes and enhancements in Symantec Endpoint Protection 12.1 Release Update 2
check this artical
https://www-secure.symantec.com/connect/articles/issue-related-low-disk-space
DWH***.tmp files are detected in the user profile temp directory
http://www.symantec.com/docs/TECH92399