I disabled the AD service on a production server on 23/07/2019. I picked up the service was restarted on the 25/07/2019. When I came to discover was that the service was used the following day around 7:52AM by users in the application.
Is it possible that the windows update restarts services without user consent.
Does Windows Update restart services without consent?
Well, Windows Update can do pretty much anything it wants, including installing, removing, or reconfiguring services. But if the updates in question didn't specifically involve the service in question, it is unlikely that the update process itself restarted a service. Particularly one that was set to Disabled. However, the Windows Update process involves a reboot most of the time, and the reboot will restart the service if the service was stopped but left in Automatic mode. (And a reboot could also trigger other actions that would cause even a Manual service to start.)
From your follow-up comment, we learn that you stopped the service, but did not disable it. Thus the service was set to either Manual or Automatic. Either way, it is reasonable to find it with a status of Running later.
If it was left at Manual:
A service set to Manual will start when either Windows or some other service needs it to be running, or when a user runs something that starts the service. In your case, this could have happened if another process needed the service, even in the absence of a reboot.
If it was left at Automatic:
A service set to Automatic will start when Windows boots up. Or, if it is stopped some time after boot-up, it will start when some other service needs it to be running, or when a user runs something that starts the service. In your case, this could have happened if your Windows Updates involved a reboot.
See also:
This question about the differences between Automatic, Manual, and Disabled
