False positive, or... SAPE.Heur.b7a1

Starting at 10 today Norton outputs the following every hour or so

 

category: Quarantine
Date & Time,Risk,Activity,Status,Recommended Action,Path - Filename
12/17/2015 10:04:33,High,73hhw4ts.dll (SAPE.Heur.b7a1) detected by Auto-Protect,Quarantined,Resolved - No Action Required,c:\users\...\appdata\local\temp\73hhw4ts.dll

A full system scan by Norton detects nothing  I notice other posts on SAPE.Heur so wonder if real  or a false positive.  If real why didn't full scan fiind anything?  Anyone else seeing?  Thanks!