SharePoint 2010 | Troubleshoot Un-sync Cummulative Update

Today, we deploy December 2013 CU and PU for Project Server 2010. After completing the binary installation, our patching process can not continue because the farm shows missing KB2553430 (December 2013 PU) in one of the server. I don’t see any technical reason why it happened, so I went through following work-around

1. Re-run the installation package using PACKAGE.BYPASS.DETECTION.CHECK=1 option (more info here). Result : unsuccessful, the impacted server is still showing that it doesn’t have KB2553430
2. Extract the installation package and install the *.msp file manually Result : unsuccessful, the impacted server is still showing that it doesn’t have KB2553430
3. Re-connect the server to the farm. Result : SUCCESS, the impacted server is successfully join to the farm with KB2553430 installed

The working workaround is actually simple, that we have to remove the impacted server from SharePoint farm, and then re-connect the server to the farm using farm passphrase. Although I can not explain why it fix the issue, I believe that this process refreshes configuration database and object references - so that the installed update are reflected properly in the farm. So next time you have same problem - just re-connect the server to the farm, and see if it refreshes the installed update.