Absynth 5.3.1 no longer loads in Synth Rack?

I used to have Absynth available from the Synth Rack. I haven't used it for over 6 months, and now it is no longer present. Projects with Absynth on a track give the "Missing Plugins" error message.
Absynth is installed, activated, and runs standalone, but is not available in Sonar Platinum.
 
I have tried to re-load Absynth in the synth rack, but it is not seen anywhere.
 
Following the NI article "Inserting a NI Instrument Plug-In", clicking the "Insert Synth" button in the Synth rack results in a sub-menu with two choices: Insert Synth, and Insert Re-wire Device.
Insert Re-wire Device only has Melodyne SingleTrack, so I ignore it.
From the Insert Synth menu, another sub-menu is displayed. It has Plug-in Layouts, a divider, and a number of sub-catetgories from bass to synth. I have explored all those options, and Absynth does not appear anywhere. NI does not appear anywhere. vst64 does not appear anywhere. The NI article (I don't know how old it is) shows a sub-menu with choices "NI" and "vst64". Those do not exist in my Sonar.
 
From the Cakewalk Plugin Manager, I have explicitly added the path to "c:\program files\native instruments\vstplugins 64 bit".
I can see Absynth in the list of VST Instruments. I had to add it to a custom plugin layout, but now Absynth 5 is seen in the Plugin Menu Layout under Synth. 
However, when I try to add Absynth to the Synth Rack, Absynth is not listed on the menu under Synth.
How do I add Absynth to the Synth Rack?
 

Thanks for the link. I noticed it was for Sonar X3.  I went up a level to https://www.cakewalk.com/Documentation/Home  and notice that X3 is the latest version shown.  Is there a different place entirely for Sonar Platinum?
 
I reviewed the local help (assuming it is for SOnar Platinum) for "Using the Synth Rack" and it is similar. The documentation seems to assume that the synth you want to insert is visible on the menus. 

I just updated to 2016.12.  Now Absynth is back again!
May have been a bug in 2016.11.   I guess that's the downside of the fast update cycle. It's nice to get new stuff sooner, but possibly there isn't as much time dedicated to regression testing.