When it comes to service packs and infrastructure updates I always recommend to wait at least 3 months to install in a production environment. This will make sure that enough real time testing will be done and bugs will be discovered if any. So that Microsoft can get ready with the necessary hot fixes for the same.
SharePoint team blog reported a similar instance last week, where a bug has been discovered in the recently released SharePoint SP2. This activates the SharePoint expiration date incorrectly resulting in converting the license in to a trial installation. This will expire the installation in 180 days after the SP2 in installed, but there is no immediate effect. There is no impact on product functioning, features or data.
A hot fix is being developed and will be released soon.