AddPackage Fails to return update was installed

Mar 3, 2015 at 10:17 AM
I'm using this API and it's great.
I am using it to update a windows embedded standard 7 machines.
I only have one small problem, one of the KBs (KB2937610) I'm updating returns a null references exception.
debugging the problem I found that this is an unhandled state in DismException.GetDismExceptionForHR because the HR returns 1 from NativeMethods.DismAddPackage
looking around this value is listed as Win32Error.ERROR_INVALID_FUNCTION.
checking the "add\remove programs->View Installed Updates" shows the update was installed.
also running the same code again shows this update to be installed.

here is the DismApi log for this update

Is Win32Error.ERROR_INVALID_FUNCTION the current value I should get?