After installing some patches and pattern updates, you may notice on the OfficeScan web console that the Summary Updates display zero (0) clients for both updated and outdated agents.
There are two different scanning methods available in OfficeScan - Conventional Scanning and Smart Scanning. If you are using Smart Scanning, the Virus Pattern column will be blank whereas the Smart Scan Agent Pattern column will contain information. On the other hand, if you are using Conventional Scanning, then the Virus Pattern column will contain information whereas the Smart Scan Agent Pattern column will be blank.
For the issue mentioned above, the Virus Pattern is showing no client because the user is currently using Smart Scan, not Conventional Scan. Therefore, it is a normal behavior.