My DS did this. My CHN called him a happy spewer. It never bothered him, and apparently it has something to do with that food flap down their throats (so technical) not being quite strong enough to hold things down when they're super full, so it kinda overflows.
Also you would be surprised how much she really is spewing up. If you spill a cup of water over your couch, floor (or even you and her) it looks like a massive amount compared to how much it was in the cup, if that makes sense...