I've set an update task in EPo for Virusscan 8.5.0 to update at 11.59. The agent is version 4. Checking the update logs of individual systems, I find that update runs at 1700 or 0800. System times are ok as is the server time. Other tasks such as on demand scan etc run at the right time. ANy ideas?
In your Task Schedule, do you have 'Enable randomization' set?
BTW it's a good idea to have randomization to save all your updates hammering the server at the same moment. I have mine set to 45 mins, which means that if I have a task time of 07:10, the client may decide to update anytime from then until 07:55. It keeps things within an hour, but does spread the load.
Do you have 'Run missed task' set to on? If so, then the missed task may run at any time.
Two things come to mind... Firstly - do you want the local Autoupdate task to run? If you don't then the policy for User Interface Policies under your VirusScan group of policies allows you to disable it (it sets it to no schedule). Check that you haven't disabled managed tasks at the same time.
Secondly - Do you see the managed tasks in the VirusScan Console? if not, try forcing a policy refresh (via Agent Status monitor - right-click on the M icon, and choose agent > status monitor).
If there is an issue either your Framework service isn't communicating properly with the server, or possibly the scheduling portion of the agent is corrupt. in either case it may be worth deploying the agent again to the affected machine(s)