Checking the VMNSDg_A.txt at %VCS_HOME%/logs would reveal below error:
VCS ERROR V-16-10051-19531 VMNSDg:
If debugging is enabled as explained in How to increase debug logging for a specific cluster resource in InfoScale Windows then below snippets will also be noticed:
VCS DBG_21 V-16-50-0 VMNSDg:
LibLogger.cpp:VLibThreadLogQueue::Dump[208]
VCS DBG_21 V-16-50-0 VMNSDg:
VMNSDg.C:VxSVCFailAction[1429]
VCS DBG_21 V-16-50-0 VMNSDg:
LibLogger.cpp:VLibThreadLogQueue::Dump[219]
The listed updates consists of Hotfix_7_4_20003_4027875_x64 that has an update for the VMNSDg.dll that adds a new attribute called DgImportWaitTimeOut to the types.cf file
The issue will be observed if the Post-installation Task for this HF fails as a part of the Update install as below:

Owing to the failure of the above task, the DgImportWaitTimeOut attribute fails to get updated in the types.cf and hence the issue.
To confirm the failure for the Post-installation task, one can also refer to the VxHF.txt from path C:\ProgramData\Veritas\VxHF, for the snippet.
VCS INFO V-16-13 Installation of hotfix Hotfix_7_4_20003_4027875_x64.exe completed successfully.
./VxHFBatchInstall.cpp:LaunchHotfixInBatchMode[1942]
VCS ERROR V-16-13 Error in executing post-installation tasks for the hotfix Hotfix_7_4_20003_4027875_x64.exe( Hotfix_7_4_20003_4027875 )
Perform the actions below to resolve the issue:
1) Browse to the path %VCS_HOME%\bin\VMNSDg and confirm that the VMNSDg.dll shows the updated version (7.4.20003.0)
The default version of the DLL would be 7.4.20000.0
2) Verify the types.cf file at path %VCS_HOME%/conf/config, shows as below:

3) After confirming the DLL is of the updated version and the VMNSDg entry shows as above in the types.cf file, the next step would be to update the types.cf with the required attributes.
To achieve this, run the InstallVMNSDgType.bat file manually from an elevated command prompt by browsing to the path C:\Program Files (x86)\Common Files\Veritas Shared\WxRTPrivates\Hotfix_7_4_20003_4027875
EXPECTED OUTPUT:

4) Confirm that the types.cf now shows below for type VMNSDg

5) Now attempt to probe the VMNSDg in the cluster and it will now probe only on the node on which this action was attempted.
NOTE: The above steps need to be repeated on all the cluster nodes that are impacted by this issue.
Unknown state even though all the required attributes are configured correctly.
This may occur for any existing VMNSDg resources or any newly added VMNSDg resource (post the update install)