You could also have problems if one is much larger than the other, but I'm assuming they're about the same size. When I first got my 2, every so often one would snap at the other when they were going for food. Once, Iggy even pulled Zeke back by his tail so he could get to the food first. It was like watching 2 kids racing for the front seat... last one there is a rotten egg! It worried me at first, then I figured out they were just playing, and now they don't do it anymore since they eat at different times.
So I guess as long as they both get to eat enough, aren't snapping at each other at other times too, and switch who gets to ride shotgun often enough, I think they'll be fine. If it continues, though, or if the biting seems like more than play, you probably want to consider separating them for feeding time. Or sending the biter to time-out to think about her actions.
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0.0.2 leos
1.0.0 spouse