This problem was fixed in Symantec Endpoint Protection 11 Maintenance Release 4 (MR4).
Event times in scheduled and alert based reports are an hour later than correct times.
Fix ID: 1299108
Symptom: Reports are an hour later than correct times.
Solution: Added a condition to determine whether the system is using daylight saving time to decide how to compute the local time.
Release notes for Symantec Endpoint Protection 11.0.x and Symantec Network Access Control 11.0.x
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2007121216360648
Migrating to Symantec Endpoint Protection 11.0 MR4
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2008121712452848