I've been seeing a bit of this this week, on a SRAM Apex compact and an FSA triple. If you've done nothing to change the chain line, look at the condition of the big ring. It will drop chain if it is bent, if it just has a bent tooth, or if it is worn and you've just put on a new chain. And it's probably not the front derailleur, but while you're down there you should be checking that too.