APM - Collecting smartcard session variable

Hmm, that's a bit strange. Can you please check and see which session variables get set/populated during your policy execution? I don't recall exactly which one is used for username reporting, but it's one of these two:

session.logon.last.logonname session.logon.last.username

You can check the value of those variables from the CLI by using the sessiondump command(so check what is set under non-debug mode). If you discover that one or the other is NOT set, try assigning the missing value during the VPE execution and see what happens.