I just installed a fresh copy of osx high sierra on an external drive just to see if it was an OS issue. I copied the entire perceptive automation folder to the new install, annd I installed the latest version of indigo.
I am getting the same behavior.
So it is not an OS related issue.
That leaves either a hardware issue, or some issue with my indigo configuration.
I haven't touched the hardware for a long time and it has worked well. There is nothing else running on this mac. It is pretty much a dedicated indigo computer.
I have the following plugins installed, and I am wondering if maybe any of them have any known issues that cause the sluggish behavior and disconnecting:
AD2USB Alarm Interface
Alexa Hue Bridge
Cynical Denon
Cynical SecuritySpy
EPS - Homebridge Buddy
Global Property Manager
Growl
NOAA Weather
Sonos
WUnderground