On Wed, Jan 22, 2014 at 8:38 AM, George Clark <geomh@fenachrone.com> wrote:
Hi Kevin,

I'm gradually thinking that I've got a haunted device.

It happens
 
Could this be a defective device?   Or just one of the mysteries of
insteon.
Or some issue with the IP modifications to the PLM code?

It is hard to say exactly what the cause is.  You seem to have a good grasp on various things to try.  I have noted, and I feel like others have as well, that the more you pester a device the worse things can become in the short term.  It might explain why you were able to scan the link table once, but then as you continued to play with it, it won't respond.  Sometime, letting things calm down solves issues.

I don't see anything that would suggest that it is a MH issue.  It just looks like normal growing pains with Insteon.

Should I go through the procedure to discover the device that is acting
as the
phase bridge / repeater on that circuit?  Swap it out with another device?
Any other ideas?

Again, it sounds like you have the right ideas.  I wish I could offer more.  All I can say is that as your network grows, these issues tend to decrease.