I had an issue today with shifting back to the big ring on the downhill of the Verrazano Bridge during the 5 borough bike tour. I also have an FSA crank, mine an SL-K on a road bike. The issue was the crank bolt coming loose, allowing the crank to move outside the range of the derailleur. I tightened it up and it was then OK.
Now your issue may not be like mine as it sounds like yours is happening even when everything is set, but I'd check the crank out thoroughly. I've had this crank for 7 years now and it has always given me problems with this. FSA changed the design on the newer versions, but never had a fix other than loctite for the old ones. That bolt never stayed tight even when torqued properly.