Using Sonar Platinum Producer:
 
After some effort today I managed to get an external effects loop (external insert) working with some new outboard gear.  However, when I solo the output bus to which this track is assigned, I hear other instruments on the bus but not the one with the external insert.  Is this is a known issue or common problem that anyone knows of or would be able to help me through?

Per http://forum.cakewalk.com/I-love-Sonars-external-insert-m2989875.aspx this does appear to be a persistent bug that has carried over from older versions of the software.  Annoying.

 
It would probably be a good idea to submit a new bug report.  Some previous bugs have been buried without being fixed and this might be one of them.  Now that so many bugs have been addressed, Cakewalk may be running out of things to do.  This might give them something with which to occupy themselves.
 
 

I have a same problem.
Another additional issue is, when "external insert" inserted on bus (not a synth or audio track)
Midi(Synth) notes could not play correctly (ignore midi notes randomly)