Hilltopper, thank you for saving these precious pups and also for sharing your story!!! Have you contacted NH Fish and Game? Perhaps it's time to speak to the bat rehabilitator again? It's possible that you are not the only one seeing this. Maybe they will want to come take a look, study and document what is happening. Are you keeping a log of these batty events? Might be very valuable information that could help save other bats. Just a thought.
Imagine how amazing an infrared video could be?!