Note that the part you quote talks abut the latecomers to a kill going for the bones. That suggests that maybe hyenas don't like the bones, but will eat them if they aren't able to get the better parts of the kill.

Another part of that same article, talking about a rare hyena that made it to old age, mentions "She still had perfect teeth, too, since her rank assured her the best cuts of meat, whereas the teeth of lower-ranking animals get chipped and worn from crunching bones", which fits in with the bones not being something that they actually want.

So maybe if an animal is killed by a hyena pack that is small enough for everyone to get a good chunk of meat, they leave the less desired bones behind?