I Hadthe same problem until about a half hour ago. I did a Factory reset and problem solved! Thanks to the help I received here.
Same here.
I had the same problem some months ago when I did a restore of system data with Titanium (so the forum diagnosed). At the time, the icon indicated something in the OS kept trying to talk to the net. The problem was when I used the Nighttime battery profile and it shut down background data, the OS never stopped trying to get on the net (looked at logs to diagnose that one). With a full charge at 8:00pm, I would have 15 - 20% by 5:00am.
My point is, while this may not be the same cause as the syncing icon after GB update, the icon
may be more than just an annoying icon. As painful as it is, I'm glad I did a reset last night and got it done with. Already today my battery seems to be doing better (though I have no hard data to support that).