I installed RTM 4351 from MS Download (https://www.microsoft.com/en-us/download/details.aspx?id=51493) and somehow end up with RC 4327. Here is the command to check your Farm Build Version.
#Check Farm Build Version
Get-SPFarm | Select BuildVersion
Upgrading to a later CU seemed to fix things, so let’s just leave that at that shall we? 🙂