Hey all!
 
For split instrument tracks, when smart mute is enabled, Sonar does not automatically mute the MIDI track when you mute the correspondig audio track (but this is how the Smart Mute is expected to work, according to the description when it was implemented). The other way around works as expected.
 

 "When enabled, SONAR’s “Smart Mute” mode for virtual instruments automatically mutes both the synth audio and MIDI tracks if either one is muted."

 Quote from https://www.cakewalk.com/...Update-Notes#smartmute
 
Can anyone reproduce?

Check the menus (right-click?) for the synth rack. I beleive there was a setup related to that there. Sorry, I'm not at my DAW right now so I can't give you exact steps.

EDIT: I see my advice is mentioned in the link you provided. Sorry! Should have checked the link BEFORE posting.

The documentation is wrong in several ways, but I don't think it really has any bearing on functionality.
 
First, the pre-Ipswich behavior  (which was effectively the same as having Smart-Mute enabled now) applied only to TTS-1, not all multi-out VSTs (EDIT: Just double-checked, and it looks like I was mistaken about that part. It does apply to other multi-out VSTs), and muting an audio output never muted a separate MIDI track. But muting a MIDI track driving a multi-out VST would mute all audio outputs.
  
The linking of Mute buttons in the two parts of a Simple Instrument track is a separate and unrelated function, as Smart-Mute is only relevant when you're using more than one output, and a Simple Instrument track by definition uses only one audio output.
 
I guess the ultimate question is: Other than the documentation being wrong/confusing, is the current functionality causing you any problem?

Brundlefly:
 
I'm mainly talking about split instruments tracks with a single output and in that case the problem is really "just" GUI visual clarity/usability - when both audio & midi are muted, it's clear even at a quick glance that the entire instrument is muted.
 
But from a purely functional point of view, in the above case, muting either of course mutes the output of the entire instrument.

The mute worked like this in X3 (muting either midi or audio always muted the other). I liked that and judging from Cakewalk's description, I think that's the logic they intended for Smart Mute as well... so I'd file it as a bug. :)

You're right; I was mistaken. Muting the audio output for an instrument with only one output or all the outputs of a multi-out synth did mute the MIDI track in X3. The documentation implies that being able to disable Smart Mute was primarily aimed at multi-out synths, but muting a single output of multi-out synth never muted the MIDI track, so it seems like it was a solution looking for a problem that didn't exist.