My DD was exactly the same. She was often so quiet that I was never sure when she woke. I did often leave her for a bit. At 3, DD still likes time by herself in bed after she wakes. It could be that your LO enjoys that quiet time to herself. I did have a tough time figuring out how to count A time after that. I ended up counting the time awake in the crib as half (so if she was awake for 30 min, I counted it as 15).
Do you want to post your EASY? Maybe a bit of tweaking will help lengthen those naps.