We often circumduct a leg to get around a clearance problem. Sometimes the clearance problem is the leg length itself, and sometimes it is a foot clearance issue, one that doesn't dorsiflex/toe extend enough.
This is what the foot clearance circumduction strategy looks like (more clear on the left foot). It is a heavy peroneal, tib anterior (more lateral belly, interosseous) and lesser toe extensor strategy. The foot clearly dorsiflexes and everts the rear and fore foot during early swing. It is not until just before heel strike that the tib anterior seem to jump in to do its primary job of dorsiflexion AND inversion.
Finding out why a client is circumducting this way is the key. It could be from the opposite hip abductors being weak, and it could be poor abdominal control on the same side, or it could be down in the foot (perhaps extensor hallucis/big toe extensor) and of highest suspect is a weak or motor pattern delayed tib anterior. Bad lazy habits can happen around trivial weakness, and then can mushroom into other bigger things.
Your exam will help you.
Seeing a problem in someones gait is not their problem, it is their strategy to get around the parts that are not working well.
shawn allen, the other gait guy