Update:  Checked the video resolution and it's already set to 32-bit, so that isn't the issue in my case.
 
Tried running the plug in an earlier version of Sonar and that seemed to somehow "kick" the plug into behaving better in S5.  But it still randomly exhibits the same strange behavior discussed in this thread.  Sometimes opening and closing Sonar seems to clear it up.  But I still haven't identified any specific reason or resolution for the behavior.
 
I'm stumped...

Only thing I can add is to make sure you're up to date with all of the updates for that version (Looks like there were two. The first patch alone, 5.0.1, has a ton of fixes).

there's also 5.0.2

Yep, all updated.  Thanks though guys for the feedback, I'm open to any ideas at all at this point.