I read over that other post and tired what they suggested but, Holy Smokes!
What a pain.
Removed each and every device from every app/automation. Then remove the Wemo devices. Then the Smartapp. Then re-install everything. And the troublemaker Wemo switch is now not detected. I will try resetting the switch locally once I get home. I sure wish Belkin would make a version of this switch that’s Z-wave or Zig-bee. I have far fewer problems with those types of switches. The downside to swapping the Wemos out is that we would loose the built in timer function that we do use a lot.
ST could help things out by not forcing you to remove a device from every automation routine
manually.
After uninstalling the old smartapp and installing the “Advanced” version of Wemo and the device types, I had to reboot my trouble switch. It was then detected by the smartapp but I started getting “Network Id must be unique” errors. Uninstalling and reinstalling the smartapp from the ST app solved this error.
I have been running 5 Wemo light switches for the last couple of days without incedint. In fact I installed the fifth switch today.
Belkin seem to have improved things on their end with new firmware and the Wemo (Connect) Advanced smartapp also seem to be working great.