I've finally started using bone animations in my models, and have recently run into a problem.

When two instances of the same model are in the scene, one of them animating sometimes effects the other.

For example, lets say I have two NPC's. One of them simply stands with a standing animation looping. The second one randomly walks around the scene. Unpredictably, the standing NPC's animation will quickly jerk to the same frame the walking NPC is at, but quickly correct itself back to the standing animation.

They don't share any variables or functions, the only connection is that they're both the same model. The same code works flawlessly with vertex animation. So I'm guessing there's something to bones I don't know about.

Am I doing something wrong? Is this normal? Is there a work around? It's unpredictable so I could almost let it slide, but when it happens it looks pretty silly.