fbriggs4:
I am attempting to get the AVR to sleep at 1uA (unsuccessfully)
To get to that level, you have to shut off EVERYTHING. The CPU clock. The Brown Out Detector. The Analog to Digital Converter. Everything. And no floating pins.
No other changes to the bread board or sketch were made so I am pretty sure it was moving the cap closer to VCC that did it.
Huh. I'm glad you found the solution. It certainly would have stumped me.