Hmm, I just did a test, and I think the issue has something to do with the local account in combination with the Disk Encryption Configuration.
I say that because my Mac has a local account enabled for FV2 as well as my AD cached mobile account on it. These both show up in the Mac record under the FileVault 2 Enabled Users list. So far so good.
Yet, when I do a search using our Disk Encryption Configuration AND that user for the FileVault 2 User criteria, it pulls up no results. If I switch to my AD account for the 2nd criteria, then it gives me results.
If I remove the Disk Encryption Configuration and only leave the FileVault 2 Enabled User criteria and plop in that local account and search, then it gives my machine as the result.
Somehow its not seeing that local account as being a valid FileVault 2 User along with the Disk Encryption Configuration, even though the record details shows it as such. Maybe its because I manually added my local account in and didn't do it through the initial FV2 enablement process. I have a feeling that's the issue.
See if searching on only the local admin account name gives you the results you want.