False positive notification - "Out of date" AV definitions

I have quite a few servers that a couple of admins have noticed this notification popping up immediately after logging in. However, the client is indeed up to date and doesnt have any errors. I'm aware of the setting in the AV policy that controls this feature and it's set to not notify until after 3 days. We are using version 12.1 RU6 MP1 and the servers are Server 2008 R2 and 2012 R2. Any ideas on what might be causing this? Thanks.