Currently Symantec Drive Encryption does not support drives with 4K Native sector size.
Drives with native 512-byte sectors are supported. Many 4K drives with 512-byte sector emulation (commonly referred to as 512e, or Advanced Format Drives) are supported as well. To determine the disk drive's sector size please see TECH198917.
Symantec Endpoint Encryption 11 has not shown any further issues with 4K drives. If issues are encountered, please submit a ticket with Symantec Support and this can be investigated further.