Had D-Fly since Day 0 of my bike with Di2...The only battery rundown issues I ran into....I traced to when I would E-Tube via phone to change the config--and forget to disconnect the phone. Di2 would stay awake and drain overnight.

Rapid battery drain means either a short (not-quite seated connector is enough), or it means something is keeping Di2 awake like the aforementioned forget-to-hangup-the-phone or a FD trim command not completed when you park etc.