Ah - this solves a mystery I encountered a couple of months ago. I got an epub that rendered correctly in ADE, but looked like this in Calibre's viewer as well as my Sony T1 (which I understand is based on ADE).
I ended up just fixing these characters in Sigil (which also rendered those characters incorrectly). I would find a garbled character in Sigil, look at that page in ADE if I couldn't figure out from the context what it was supposed to be, and do a global replace in Sigil (across all html files) to change it to the equivalent html & code. These rendered correctly everywhere.
I think I found them all, but haven't read the book yet to be sure.