Starting with ESX/ESXi 4.0, the vSphere Client automatically reconnects to a host after being disconnected during a host reboot. Earlier versions of the software do not reconnect automatically, and do not experience this issue. To resolve these issues, close the vSphere Client and reconnect to the host or vCenter Server with a new session of the client.
After taking these steps, if your host has been properly rebooted during the patching routine, your new connection with vSphere Client will show the correct status and build number for the host.