[cypher]

It does sound as though it could be a problem with Beans teeth, you could try holding a treat just above her head so you can see her teeth as she reaches up & opens her mouth to take it, if that doesn't work then a vet check will be the best thing.
As RH mentioned sometimes with pairs the more dominant one will prevent the other from getting enough food so even though there is a stash there she may not be able to get adequate food, have you seen any other signs of bullying or falling out between the two?
While you wait to see the vet you can feed soft foods, either soaked hamster mix, porridge/oatmeal or hamster safe baby foods, this might be tricky with a pair though as you won't be sure that it's Beans who's getting it if you leave it in the cage, you could try hand feeding some but it is important that she has food she can eat available all the time so ideally it would need to be left in the cage.