ESXi 5.0 host upgraded to 5.1 doesn't auto reconnect to vCenter 5.1 - Cannot synchronize host error on vSphere client?

I have a host running ESXi 5.0 GA and it is registered with a vCenter 5.1 Server (Windows or VCVA). After upgrading the host to ESXi 5.1 using the commands below and rebooting, it doesn't automatically reconnect to vCenter.

# esxcli software profile update -d {path}/VMware-ESXi-5.1.0-799733-depot.zip -p ESXi-5.1.0-799733-standard

The vSphere client show the host status as not responding and the message "Cannot synchronize host ip-addr. A general system error occurred: invalid response" is shown in the yellow configuration issues box on the summary tab.  If I right-click the host and select "Connect" it does connect and is fine from there on out. 

Is this a known issue?  expected behavior?

thanks

kevin