Another update:
As I type this, my handheld is in a box waiting on the man in the brown shirt to pick it up and send it to Garmin Intl. in Olathe, Kansas.
I have had a few strange things happen with my handheld, first is the issue that started this thread, then during a number of recent hunts I have had the screen go completely blank. I am not sure if the unit is powering off, or if the screen is just blanking out. Whatever it is, I can hit the power button, and the display comes on and is immediately tracking the dogs.
Last thing happened on my last hunt. I was dropping the dogs at 100 yards or less. no difference between the factory rubber antenna and the long range antenna.
This morning I called Garmin tech support. We tried a few things, removing all collars and reloading them. No improvement. We did a master reset, then reloaded collars. Again no improvement. So the tech said to send the unit in to them and they would repair it. I mentioned that I have had it for close to a year, and that it could actually be a little over a year old. He said not to worry and that they would repair the unit free of charge, and have it back to me within two weeks! By rights they could have had me provide a proof of purchase, and tell me it's out of warranty, then charge me. They sure impressed me today with their attitude toward customer service.